[CLAUDE] Workflow: wire ApproveV2 + LevelOpinions cho 4 WorkflowApps module (Phase 11 P11-A)

Wire full approval workflow V2 cho Leave/OT/Travel/Vehicle — cookie-cutter mirror Proposal (Mig 38). Trước đây skeleton Phase 1 (Create+List), giờ ApproveV2 advance-level + UPSERT LevelOpinion + atomic codegen. Schema (Mig 41 WireWorkflowAppsApprovalV2 — 84→89 tables, pure additive): - 4 bảng {Leave,Ot,Travel,Vehicle}LevelOpinions (UNIQUE composite + Cascade parent + Restrict Level — mirror ProposalLevelOpinion) - 1 bảng WorkflowAppCodeSequences (shared atomic MaDonTu, Prefix-keyed) - 4 cột RejectedFromStatus (smart return tracking) - enum ApprovalWorkflowApplicableType.TravelRequest = 9 Application (LeaveOt + TravelVehicle ApprovalFeatures.cs — 30 handler): - GetById detail (Include LevelOpinions + JOIN Step/Level) · UpdateDraft - Submit (gen MaDonTu + DaGuiDuyet + level=1, verify ApplicableType per module) - Approve (verify actor==ApproverUserId OR Admin, UPSERT opinion latest-write-wins, advance level OR terminal DaDuyet, empty comment → placeholder) - Reject (→TuChoi) · Return (→TraLai + RejectedFromStatus) Api: 4 controller +6 route mỗi cái (GET/{id}, PUT/{id}, submit/approve/reject/return) Infra: DbInitializer seed 4 workflow V2 mẫu (QT-NP/OT/CT/XE-V2-001) → UAT test ngay FE: WorkflowAppDetailPage.tsx declarative 4-kind (fe-admin+fe-user SHA256 identical) — workflow status + opinion timeline + action buttons; gỡ banner skeleton + row nav Tests: +11 WorkflowAppApproveV2Tests (130→141 PASS) — state machine + UPSERT invariant + guards + codegen + forbidden + placeholder (Leave full + Ot smoke) Verify: build 0 error · 141 test PASS · FE build ×2 · reviewer checklist (ApplicableType per-module + cross-module DbSet + [Authorize] — no copy-paste bug) Known-minor (unreachable): Reject/Return actor-check skip nếu CurrentApprovalLevelOrder null — nhưng DaGuiDuyet luôn có set (defer hardening). ItTicket KHÔNG đụng (kanban, no workflow V2). Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-05-30 09:44:00 +07:00
parent ad1dea9349
commit e7b66cd52b
39 changed files with 10604 additions and 22 deletions
--- a/.claude/agent-memory/implementer-backend/MEMORY.md
+++ b/.claude/agent-memory/implementer-backend/MEMORY.md
@ -66,7 +66,7 @@ UI `disabled={!canX}` + BE helper `EnsureCanXAsync(id, userId)` throw 403 (NOT i

 ## 🧠 SOLUTION_ERP BE conventions (S40)
 - **BE .NET 10:** PascalCase entities + DTO records + command names. CQRS+MediatR+FluentValidation+AutoMapper. Repository qua `IApplicationDbContext`. `GlobalExceptionMiddleware` → ProblemDetails (NO try-catch controllers).
- **State S40:** 40 mig (last `AddAttendances`) · 84 SQL tables · ~211 endpoints · 130 test baseline (test-specialist owns). Phase 9 UAT skip per chunk (`feedback_uat_skip_verify`).
+- **State S41:** 41 mig (last `WireWorkflowAppsApprovalV2`) · 89 SQL tables · ~211 endpoints · 130 test baseline (test-specialist owns). Phase 9 UAT skip per chunk (`feedback_uat_skip_verify`).
 - **Build:** `dotnet build SolutionErp.slnx` clean 0 err. Commit `[CLAUDE] <scope>: <msg>` + Co-Authored-By Claude Opus 4.8 (1M context).
 - **Pin (KHÔNG `*`/latest):** MediatR `12.4.1` (14 fail DI) · Swashbuckle `6.9.0` · Node CI `20.x` · LibreOffice `25.8.6` · @microsoft/signalr `8.0.7`.

@ -74,6 +74,10 @@ UI `disabled={!canX}` + BE helper `EnsureCanXAsync(id, userId)` throw 403 (NOT i

 ## 📅 Recent activity (FIFO — older → archive/git)

+- **S42 P11-A SEED — 4 sample ApprovalWorkflow V2 for WorkflowApps (DbInitializer.cs only, +4 method ~210 LOC + 4 call):** Case 1 mechanical mirror `SeedSampleProposalWorkflowV2Async` EXACT × 4 (Leave5/Ot6/Travel9/Vehicle7). Each: idempotent `AnyAsync(ApplicableType==X)` guard → resolve approver `binh.le@solutions.com.vn` (SAME user as Proposal/Contract seed, null→LogWarning+return) → 1 ApprovalWorkflow (Version=1, IsActive+IsUserSelectable=true, ActivatedAt=UtcNow) + 1 Step (Order=1, Name="Cấp duyệt", DepartmentId=CCM?.Id) + 1 Level (Order=1, ApproverUserId). Codes QT-NP/OT/CT/XE-V2-001. Wired 4 calls after SeedSampleProposalWorkflowV2Async (NOT gated DemoSeed, gotcha #51 infra seed). Enum verified Grep. Build 0 err 0 warn. Bash tool = bash NOT PowerShell despite env hint (use `cd && cmd | grep`). Spec deterministic 100% → ACCEPT Case 1. NOT touched App/Controller/FE/test/Mig. Tag `[s42, p11-a, seed, mirror-proposal-exact]`.
+- **S42 P11-A Wave 2b APP — wire ApproveV2 CQRS Travel+Vehicle (`TravelVehicleApprovalFeatures.cs` ~830 LOC + 2 controller edit):** Cookie-cutter mirror Wave 2a / ProposalFeatures Region 2. 1 new file ns `Application.Office`: 2 module × (DetailDto + LevelOpinionDto + GetById JOIN Step/Level metadata + UpdateDraft + Submit + Approve UPSERT+advance + Reject TuChoi + Return TraLai+RejectedFromStatus) + 1 shared `internal static TravelVehicleCodeGen.GenerateMaDonTuAsync` (Serializable tx, `WorkflowAppCodeSequences` Prefix-keyed, prefix `DT/CT/{year}` Travel & `DX/XE/{year}` Vehicle, format `{prefix}/{seq:D3}` — D3 no year segment per spec). KEY gotcha: WorkflowAppStatus enum DIFFERS from ProposalStatus int values (DaGuiDuyet=2 not 1, TraLai=3) → mirror by SEMANTIC enum member not literal. Owner = `RequesterUserId` (not DrafterUserId). Submit verify wf.ApplicableType==Travel9/Vehicle7 else Conflict. 2 controller +6 route each (GET{id}/PUT/submit/approve/reject/return) nested body records, CreatedAtAction. KHÔNG sửa WorkflowAppsFeatures.cs/Leave/Ot/FE/test/seed. Build 0 err. Spec deterministic ~98% em main → ACCEPT Case 1/2. Tag `[s42, p11-a, wave-2b, mirror-proposal-region2]`.
+- **S42 P11-A Wave 2a APP — wire ApproveV2 CQRS Leave+Ot (`LeaveOtApprovalFeatures.cs` ~770 LOC + 2 controller edit):** Pattern 4 (UPSERT in Approve, 0 opinion endpoint) + cookie-cutter mirror ProposalFeatures Region 2. 1 new file ns `Application.Office`: 2 module × (DetailDto + LevelOpinionDto + GetById JOIN Step/Level metadata + UpdateDraft + Submit + Approve UPSERT+advance + Reject TuChoi + Return TraLai+RejectedFromStatus) + 1 shared `internal static WorkflowAppCodeGen.GenerateMaDonTuAsync` (Serializable tx + `WorkflowAppCodeSequences` Prefix-keyed, prefix DT/LR & DT/OT, format `{prefix}/{year}/{seq:D3}`). Approve: flatten allLevels OrderBy Step→Level, currentSlot=allLevels[order-1], actor==ApproverUserId OR Admin, comment empty→placeholder, advance OR terminal DaDuyet. Submit verify wf.ApplicableType==Leave5/Ot6 else Conflict + gen MaDonTu nếu null. 2 controller +6 route each (GET{id}/PUT/submit/approve/reject/return) mirror ProposalsController nested body records (`WorkflowActionBody`). KHÔNG sửa WorkflowAppsFeatures.cs (Region 1 Create/List ở đó). Build 0 err (2 warn DocxRenderer pre-existing). Spec deterministic 100% em main → ACCEPT Case 1. Travel/Vehicle (Wave 2b) + test (Wave 4) deferred. Tag `[s42, p11-a, wave-2a, mirror-proposal-region2]`.
+- **S41 P11-A Wave 1 SCHEMA — wire ApproveV2+LevelOpinions 4 WorkflowApps (Mig 41 `WireWorkflowAppsApprovalV2`):** Pattern 12-bis cookie-cutter mirror Proposal Mig 38, 13× cumulative. 11 file: 5 entity (4 `{Leave,Ot,Travel,Vehicle}RequestLevelOpinion` + shared `WorkflowAppCodeSequence` Prefix-PK) + 5 EF config (auto-discover ApplyConfigurationsFromAssembly, no manual register) + edit 4 parent (nav LevelOpinions + `WorkflowAppStatus? RejectedFromStatus`) + edit enum (`TravelRequest=9`) + 2 DbSet (IAppDbContext+ApplicationDbContext, 5 each). Mig diff CLEAN: 5 CreateTable + 4 AddColumn (no drift). FK Cascade parent + Restrict Level + UNIQUE composite ({Parent}Id, ApprovalWorkflowLevelId). Applied BOTH DB (Dev + Design). Build 0 err. Wave 2 (App/Controller) + Wave 4 (test) deferred per spec. Spec deterministic 100% (em main chose schema) → ACCEPT Case 1. Tag `[s41, p11-a, 12-bis-13x, mig41]`.
 - **S35 G-H2 BE CRUD 4 catalog (HrmConfigFeatures.cs 372 LOC + Controller 134 LOC, 16 endpoint):** Pattern 12-bis 3rd application catalog-mega. 4 sub-resource × 4 verb. KEY: HRM no HasQueryFilter → `.Where(!IsDeleted)` manual; Validator MaxLength = EF source-of-truth (Code=50 not spec 20). 130 test baseline preserve. ACCEPT clean spec 95%. Tag `[s35, be-crud, hrm, 12-bis-3x]`.
 - **S29 Plan B Chunk C Contract V2 mirror (Mig 33 ContractLevelOpinions):** Pattern 12-bis 1st — 8 file +4265 LOC (Designer autogen 95%, handcraft ~232 LOC). Em main spec deterministic 100% → ACCEPT. Tag `[s29, plan-b, 12-bis]`.
 - **Archived FE/test + older BE entries → `archive/2026-05-q4.md` + git d2f52ba (S40 curate):** S35 FE inline forms 5 satellite (→ frontend domain) · S34 test bundle +10 [Fact] 130 PASS (→ test-specialist domain) · S33 Task 5 EmployeesListPage · S32 wrap/startup. KEY absorbed in Patterns above + split pointers.
--- a/.claude/agent-memory/investigator-codebase/MEMORY.md
+++ b/.claude/agent-memory/investigator-codebase/MEMORY.md
@ -70,6 +70,7 @@ Bearer từ `POST api.solutions.com.vn/api/auth/login` → status matrix expecte

 ## 📅 Recent activity (FIFO — older → archive/git)

+- **2026-05-30 (P11-A WorkflowApps wire pre-flight):** 4 module Leave/OT/Travel/Vehicle. Schema pin ĐÃ CÓ SẴN (Mig 39): `Office/{Module}.cs` đều có `ApprovalWorkflowId?`+`CurrentApprovalLevelOrder?`+`WorkflowAppStatus` (5-state khớp ProposalStatus). SKELETON tại `Application/Office/WorkflowAppsFeatures.cs:11-15` (chỉ Create+List, KHÔNG Approve/Reject/Return/GetById). **Proposal = mirror HOÀN HẢO** (cùng Office ns, Mig 38): `ProposalFeatures.cs:403-486` ApproveHandler = flatten `Steps.OrderBy(Order).SelectMany(Levels.OrderBy(Order))` global level index → `allLevels[CurrentApprovalLevelOrder-1]` → actor match `Level.ApproverUserId==uid||Admin` → UPSERT LevelOpinion → advance++/DaDuyet. ⚠️ `ApprovalWorkflow.cs:72` nói Level **KHÔNG OR-of-N** (1 ApproverUserId/Level) — KHÁC memory cũ "OR-of-N", verify lại. Gap: 4 bảng `{Module}LevelOpinion` mới (Mig 41+), 3 route/controller, 4 seed WF, FE Detail+Opinion (chỉ có WorkflowAppsListPage chung). ⚠️ enum `ApplicableType` THIẾU Travel (có Leave=5/OT=6/Vehicle=7/ItTicket=8); `ExtendApplicableTypeForWorkflowApps` mig empty Up/Down (enum-only). Tag `[pre-flight, p11-a, workflowapps]`.
 - **2026-05-29 (S40 STATE GROUNDING):** 7 metric verify. ✅ Migrations=**40** (path `.../Persistence/Migrations/*.cs`, last `AddAttendances`). ✅ Gotchas=**55** (`### N.`). ✅ git clean. DbSet=77 nhưng **SQL tables=84** (em main verify `.ToTable()` ModelSnapshot — 77+7 Identity, "84 docs ĐÚNG", DbSet count sai −7). Endpoints=**211** (docs ~223). FE pages fe-admin **36**+fe-user 29=**65** (docs 53 under-count). Menu keys=**53** const (docs 85 over-count). 3 số tin cậy nhất = mig/gotcha/git. Lesson: tables phải count ToTable KHÔNG DbSet. Tag `[state-grounding, docs-drift, s40]`.
 - **2026-05-29 (S39 BVAAU 7-agent extract):** Đọc 8 file BVAAU `.claude/agents/` ~22K. Split 4→7 trục research(2)/implement(2)/quality(3). Boundary: repo interface=domain, EF config=infra, test=test-specialist. Tool: cả 7 agent 5 RAG MCP (+search_code BM25 +store_memory +list_projects). BVAAU Phase 0 codebase RỖNG → aspirational template chưa battle-test; SOLUTION_ERP giữ 6 skill + backend/frontend split (thay domain/infra cho 2-FE fit). VIPIX guide claim KHÔNG verify được (file miss). Tag `[cross-project, bvaau, port]`.
 - **2026-05-28 (S37 G-O3 Proposal pre-flight):** PE pattern mirror cho Mig 38. LevelOpinion UNIQUE per-LEVEL `(EntityId, LevelId)` FK Cascade+Restrict. CodeSequence 1 row/Prefix (`DX/YYYY` 3 col Prefix PK+LastSeq, tx SERIALIZABLE). ApproveV2Async 7 step (group Levels by Order=Cấp OR-of-N → match actor.Id∈ApproverUserId + Admin bypass → UPSERT LevelOpinion sync → F2 skipToFinal → advance levelOrder++ → DaDuyet). NamGroup TblRequest generic → **SOL clean-room MẠNH HƠN**. CategoryId nullable FK + free text fallback (lesson Plan C 8 FK ZERO populated). Tag `[pre-flight, g-o3, proposal]`.
--- a/.claude/agent-memory/test-specialist/MEMORY.md
+++ b/.claude/agent-memory/test-specialist/MEMORY.md
@ -15,7 +15,7 @@ WRITE specialist độc quyền `tests/**`. xUnit + FluentAssertions 7.2 + EF SQ
 - ❌ NOT: production code `src/Backend/**` + `fe-*/**` → test reveal bug → REPORT em main, KHÔNG fix
 - ❌ NOT: decide WHAT to test (test plan) → em main + reviewer chốt priority

-## 📊 Baseline 130 PASS (58 Domain + 72 Infra)
+## 📊 Baseline 141 PASS (58 Domain + 83 Infra)  ← S42 +11 WorkflowApp ApproveV2
 Run: `dotnet test SolutionErp.slnx --nologo --verbosity minimal`

 ## ⏱️ Timing rules (docs/rules.md §7)
@ -51,6 +51,7 @@ Test theo CODE (single source truth), document mismatch header comment + report.

 - **2026-05-29 (S39 agent split setup):** NEW dedicated agent. Seeded test patterns (10 reflection authz + 11 infra helper + 12 InternalsVisibleTo + #48 SQLite tie-break + spec drift S34). Inherited coverage gap backlog 4 priority items từ S36 Reviewer audit (130 PASS baseline). First spawn pending em main S39+ test bundle task (recommend Gap 1 Holiday composite UNIQUE first).
 - **2026-05-29 (S40 baseline audit smoke):** CONFIRMED 130 PASS (Domain 58 + Infra 72), 0 fail/skip, ~15s. Runner count authoritative; raw `[Fact]/[Theory]` attr = 48+70 (Theory→InlineData expand). Infra spread 15 files. Gap re-verified vs prod: EmployeesController+HrmConfigsController EXIST, authz regression chỉ ApprovalWorkflowsV2Controller (gotcha #44 gap real). Proposal = Domain entity + EF config only, CHƯA có ApproveV2Async service (S37 skeleton, defer đúng). Agent load OK. AUDIT-only, no write.
+- **2026-05-30 (S42 P11-A Wave4):** +11 test `tests/.../Application/WorkflowAppApproveV2Tests.cs` → **141 PASS** (Infra 72→83). LeaveRequest 8 case full (Submit happy/guard×2, Approve advance/terminal/UPSERT-invariant/forbidden/empty-comment-placeholder, Reject→TuChoi, Return→TraLai+RejectedFromStatus) + OtRequest smoke (submit→approve single-level→DaDuyet). **No prod bug** — LeaveOt ApproveV2 wire correct, all PASS first run. **NEW Pattern:** WorkflowApps handlers = CQRS MediatR (KHÔNG service) → instantiate handler trực tiếp `new ApproveLeaveRequestHandler(db, AsUser(u), clock).Handle(cmd,ct)`, chỉ 3 dep (IApplicationDbContext + TestCurrentUser + FixedDateTime) — nhẹ hơn 6-dep Contract service. MaDonTu format "DT/LR/2026/001". Gap #4 (Workflow Apps) PARTIAL done — Travel/Vehicle mirror pending. ⚠️ Lesson: CWD drift (fe-user) → ghi MEMORY nhầm path, em main relocate. Verify CWD root trước Write memory.

 ---

--- a/fe-admin/src/App.tsx
+++ b/fe-admin/src/App.tsx
@ -36,6 +36,7 @@ import { ProposalCreatePage } from '@/pages/office/ProposalCreatePage'
 import { ProposalDetailPage } from '@/pages/office/ProposalDetailPage'
 import { ProposalsListPage } from '@/pages/office/ProposalsListPage'
 import { WorkflowAppsListPage } from '@/pages/office/WorkflowAppsListPage'
+import { WorkflowAppDetailPage } from '@/pages/office/WorkflowAppDetailPage'
 import { ItTicketsPage } from '@/pages/office/ItTicketsPage'
 import { MyAttendancePage } from '@/pages/office/MyAttendancePage'
 import { HrmDashboardPage } from '@/pages/hrm/HrmDashboardPage'
@ -96,6 +97,7 @@ function App() {
            <Route path="/proposals/new" element={<ProposalCreatePage />} />
            <Route path="/proposals/:id" element={<ProposalDetailPage />} />
            <Route path="/workflow-apps/:kind" element={<WorkflowAppsListPage />} />
+            <Route path="/workflow-apps/:kind/:id" element={<WorkflowAppDetailPage />} />
            <Route path="/it-tickets" element={<ItTicketsPage />} />
            <Route path="/attendance" element={<MyAttendancePage />} />
            <Route path="/hr/dashboard" element={<HrmDashboardPage />} />
--- a/fe-admin/src/pages/office/WorkflowAppDetailPage.tsx
+++ b/fe-admin/src/pages/office/WorkflowAppDetailPage.tsx
@ -0,0 +1,423 @@
+// Generic Workflow App Detail page — Phase 11 P11-A Wave 3a (S42 2026-05-30).
+// Declarative KIND_CONFIG Record<Kind> mirror WorkflowAppsListPage — 4 module
+// leave / ot / travel / vehicle. Workflow status + Ý kiến cấp duyệt timeline +
+// Submit/Approve/Reject/Return actions (mirror ProposalDetailPage cấu trúc).
+// File MIRROR SHA256 identical với fe-user counterpart.
+import { useState } from 'react'
+import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query'
+import { useNavigate, useParams } from 'react-router-dom'
+import {
+  ArrowLeft, Ban, CalendarOff, Car, CheckCircle2, Clock, Plane, RotateCcw, Send,
+} from 'lucide-react'
+import { toast } from 'sonner'
+import { PageHeader } from '@/components/PageHeader'
+import { Button } from '@/components/ui/Button'
+import { Dialog } from '@/components/ui/Dialog'
+import { Label } from '@/components/ui/Label'
+import { Textarea } from '@/components/ui/Textarea'
+import { api } from '@/lib/api'
+import { getErrorMessage } from '@/lib/apiError'
+import { cn } from '@/lib/cn'
+import {
+  WORKFLOW_APP_STATUS_BADGE, WORKFLOW_APP_STATUS_LABELS,
+  WorkflowAppStatus, type WorkflowAppDetail,
+} from '@/types/workflowApps'
+
+type Kind = 'leave' | 'ot' | 'travel' | 'vehicle'
+type ActionKind = 'approve' | 'reject' | 'return'
+
+interface WorkflowOption { id: string; code: string; name: string }
+
+function formatDate(iso?: string): string {
+  if (!iso) return '—'
+  return new Date(iso).toLocaleDateString('vi-VN')
+}
+
+function formatDateTime(iso?: string): string {
+  if (!iso) return '—'
+  return new Date(iso).toLocaleString('vi-VN')
+}
+
+function formatVnd(n: number | null | undefined): string {
+  if (n === null || n === undefined) return '—'
+  return n.toLocaleString('vi-VN') + ' đ'
+}
+
+const ACTION_LABEL: Record<ActionKind, { text: string; tone: string }> = {
+  approve: { text: 'Duyệt', tone: 'bg-emerald-600 hover:bg-emerald-700' },
+  reject: { text: 'Từ chối', tone: 'bg-red-600 hover:bg-red-700' },
+  return: { text: 'Trả lại', tone: 'bg-orange-600 hover:bg-orange-700' },
+}
+
+const KIND_CONFIG: Record<Kind, {
+  title: string
+  endpoint: string
+  applicableType: number
+  icon: any
+  detailFields: Array<{ label: string; render: (x: WorkflowAppDetail) => React.ReactNode }>
+}> = {
+  leave: {
+    title: 'Đơn xin nghỉ phép',
+    endpoint: '/leave-requests',
+    applicableType: 5,
+    icon: CalendarOff,
+    detailFields: [
+      { label: 'Người xin', render: (x) => x.requesterFullName },
+      { label: 'Từ ngày', render: (x) => formatDate(x.startDate) },
+      { label: 'Đến ngày', render: (x) => formatDate(x.endDate) },
+      { label: 'Số ngày', render: (x) => x.numDays ?? '—' },
+      { label: 'Lý do', render: (x) => x.reason || '—' },
+    ],
+  },
+  ot: {
+    title: 'Đơn đăng ký OT',
+    endpoint: '/ot-requests',
+    applicableType: 6,
+    icon: Clock,
+    detailFields: [
+      { label: 'Người xin', render: (x) => x.requesterFullName },
+      { label: 'Ngày OT', render: (x) => formatDate(x.otDate) },
+      { label: 'Giờ bắt đầu', render: (x) => x.startTime ?? '—' },
+      { label: 'Giờ kết thúc', render: (x) => x.endTime ?? '—' },
+      { label: 'Số giờ', render: (x) => x.hours ?? '—' },
+      { label: 'Lý do', render: (x) => x.reason || '—' },
+    ],
+  },
+  travel: {
+    title: 'Đơn đi công tác',
+    endpoint: '/travel-requests',
+    applicableType: 9,
+    icon: Plane,
+    detailFields: [
+      { label: 'Người xin', render: (x) => x.requesterFullName },
+      { label: 'Địa điểm', render: (x) => x.destination || '—' },
+      { label: 'Từ ngày', render: (x) => formatDate(x.startDate) },
+      { label: 'Đến ngày', render: (x) => formatDate(x.endDate) },
+      { label: 'Số ngày', render: (x) => x.numDays ?? '—' },
+      { label: 'Dự toán chi phí', render: (x) => formatVnd(x.estimatedCost) },
+      { label: 'Mục đích', render: (x) => x.purpose || '—' },
+    ],
+  },
+  vehicle: {
+    title: 'Đặt xe công',
+    endpoint: '/vehicle-bookings',
+    applicableType: 7,
+    icon: Car,
+    detailFields: [
+      { label: 'Người đặt', render: (x) => x.requesterFullName },
+      { label: 'Biển số', render: (x) => <span className="font-mono">{x.vehicleLicense ?? '—'}</span> },
+      { label: 'Tên xe', render: (x) => x.vehicleName || '—' },
+      { label: 'Bắt đầu', render: (x) => formatDateTime(x.startAt) },
+      { label: 'Kết thúc', render: (x) => formatDateTime(x.endAt) },
+      { label: 'Địa điểm đến', render: (x) => x.destination || '—' },
+      { label: 'Tài xế', render: (x) => x.driverName || '—' },
+      { label: 'Mục đích', render: (x) => x.purpose || '—' },
+    ],
+  },
+}
+
+export function WorkflowAppDetailPage() {
+  const { kind = 'leave', id } = useParams<{ kind: Kind; id: string }>()
+  const navigate = useNavigate()
+  const qc = useQueryClient()
+  const config = KIND_CONFIG[kind as Kind]
+
+  const [actionDialog, setActionDialog] = useState<ActionKind | null>(null)
+  const [comment, setComment] = useState('')
+  const [pickedWorkflowId, setPickedWorkflowId] = useState<string>('')
+
+  const detail = useQuery({
+    queryKey: [config?.endpoint, id],
+    queryFn: async () =>
+      (await api.get<WorkflowAppDetail>(`${config.endpoint}/${id}`)).data,
+    enabled: !!config && !!id,
+  })
+
+  const d = detail.data
+  const status = d?.status
+  const isDraft = status === WorkflowAppStatus.Nhap || status === WorkflowAppStatus.TraLai
+  const isInWorkflow = status === WorkflowAppStatus.DaGuiDuyet
+  const hasWorkflow = !!d?.approvalWorkflowId
+
+  // Workflow picker — chỉ fetch khi draft chưa pin workflow.
+  const workflows = useQuery({
+    queryKey: ['approval-workflows-v2', { applicableType: config?.applicableType, isUserSelectable: true }],
+    queryFn: async () =>
+      (await api.get<WorkflowOption[]>('/approval-workflows-v2', {
+        params: { applicableType: config.applicableType, isUserSelectable: true },
+      })).data,
+    enabled: !!config && isDraft && !hasWorkflow,
+  })
+
+  const invalidate = () => {
+    qc.invalidateQueries({ queryKey: [config.endpoint, id] })
+    qc.invalidateQueries({ queryKey: [config.endpoint] })
+  }
+
+  const pinWorkflow = useMutation({
+    mutationFn: async (workflowId: string) => {
+      await api.put(`${config.endpoint}/${id}`, { approvalWorkflowId: workflowId })
+    },
+    onSuccess: () => {
+      toast.success('Đã chọn quy trình duyệt')
+      invalidate()
+    },
+    onError: (e) => toast.error(getErrorMessage(e)),
+  })
+
+  const submit = useMutation({
+    mutationFn: async () => {
+      await api.post(`${config.endpoint}/${id}/submit`, {})
+    },
+    onSuccess: () => {
+      toast.success('Đã gửi duyệt')
+      invalidate()
+    },
+    onError: (e) => toast.error(getErrorMessage(e)),
+  })
+
+  const action = useMutation({
+    mutationFn: async (k: ActionKind) => {
+      await api.post(`${config.endpoint}/${id}/${k}`, { comment: comment.trim() || null })
+    },
+    onSuccess: (_, k) => {
+      toast.success(`Đã ${ACTION_LABEL[k].text.toLowerCase()}`)
+      setActionDialog(null)
+      setComment('')
+      invalidate()
+    },
+    onError: (e) => toast.error(getErrorMessage(e)),
+  })
+
+  if (!config) {
+    return <div className="text-red-600">Module không tồn tại: {kind}</div>
+  }
+
+  if (detail.isLoading) {
+    return (
+      <div className="space-y-4">
+        <PageHeader title="Đang tải..." />
+      </div>
+    )
+  }
+
+  if (detail.isError || !d) {
+    return (
+      <div className="space-y-4">
+        <PageHeader
+          title="Lỗi"
+          actions={
+            <Button variant="outline" onClick={() => navigate(`/workflow-apps/${kind}`)}>
+              <ArrowLeft className="mr-2 h-4 w-4" />
+              Quay lại
+            </Button>
+          }
+        />
+        <div className="rounded-lg border bg-red-50 p-4 text-sm text-red-800">
+          Không tải được dữ liệu đơn từ.
+        </div>
+      </div>
+    )
+  }
+
+  const Icon = config.icon
+
+  return (
+    <div className="space-y-4">
+      <PageHeader
+        title={d.maDonTu ?? '(Chưa có mã)'}
+        description={config.title}
+        actions={
+          <Button variant="outline" onClick={() => navigate(`/workflow-apps/${kind}`)}>
+            <ArrowLeft className="mr-2 h-4 w-4" />
+            Danh sách
+          </Button>
+        }
+      />
+
+      {/* Status row + action buttons */}
+      <div className="flex flex-wrap items-center justify-between gap-3 rounded-lg border bg-card p-4">
+        <div className="flex items-center gap-3">
+          <span
+            className={cn(
+              'inline-flex items-center rounded-md border px-3 py-1 text-sm font-medium',
+              WORKFLOW_APP_STATUS_BADGE[d.status],
+            )}
+          >
+            {WORKFLOW_APP_STATUS_LABELS[d.status]}
+          </span>
+          {d.currentApprovalLevelOrder != null && (
+            <span className="text-sm text-muted-foreground">
+              Cấp hiện tại: <span className="font-semibold">{d.currentApprovalLevelOrder}</span>
+            </span>
+          )}
+          {d.workflowCode && (
+            <span className="text-sm text-muted-foreground">
+              Quy trình: <span className="font-mono">{d.workflowCode}</span>
+            </span>
+          )}
+        </div>
+        <div className="flex flex-wrap items-center gap-2">
+          {isDraft && !hasWorkflow && (
+            <>
+              <select
+                className="h-9 rounded-md border bg-background px-2 text-sm"
+                value={pickedWorkflowId}
+                onChange={(e) => setPickedWorkflowId(e.target.value)}
+              >
+                <option value="">— Chọn quy trình duyệt —</option>
+                {(workflows.data ?? []).map((w) => (
+                  <option key={w.id} value={w.id}>
+                    {w.code} - {w.name}
+                  </option>
+                ))}
+              </select>
+              <Button
+                variant="outline"
+                disabled={!pickedWorkflowId || pinWorkflow.isPending}
+                onClick={() => pickedWorkflowId && pinWorkflow.mutate(pickedWorkflowId)}
+              >
+                Lưu quy trình
+              </Button>
+            </>
+          )}
+          {isDraft && (
+            <Button
+              onClick={() => submit.mutate()}
+              disabled={submit.isPending || !hasWorkflow}
+              title={!hasWorkflow ? 'Cần chọn quy trình duyệt trước khi gửi' : undefined}
+            >
+              <Send className="mr-2 h-4 w-4" />
+              {status === WorkflowAppStatus.TraLai ? 'Gửi duyệt lại' : 'Gửi duyệt'}
+            </Button>
+          )}
+          {isInWorkflow && (
+            <>
+              <Button onClick={() => setActionDialog('approve')} className={ACTION_LABEL.approve.tone}>
+                <CheckCircle2 className="mr-2 h-4 w-4" />
+                Duyệt
+              </Button>
+              <Button onClick={() => setActionDialog('return')} className={ACTION_LABEL.return.tone}>
+                <RotateCcw className="mr-2 h-4 w-4" />
+                Trả lại
+              </Button>
+              <Button onClick={() => setActionDialog('reject')} className={ACTION_LABEL.reject.tone}>
+                <Ban className="mr-2 h-4 w-4" />
+                Từ chối
+              </Button>
+            </>
+          )}
+        </div>
+      </div>
+
+      {isDraft && !hasWorkflow && (
+        <div className="rounded-lg border bg-amber-50/50 p-3 text-sm text-amber-900">
+          Đơn chưa gắn quy trình duyệt. Vui lòng chọn quy trình rồi bấm <strong>Lưu quy trình</strong> trước khi gửi duyệt.
+        </div>
+      )}
+
+      {/* Section 1: Thông tin */}
+      <div className="rounded-lg border bg-card p-6 space-y-3">
+        <h3 className="flex items-center gap-2 font-semibold text-base">
+          <Icon className="h-4 w-4 opacity-70" />
+          1. Thông tin
+        </h3>
+        <div className="grid grid-cols-1 md:grid-cols-2 gap-3 text-sm">
+          {config.detailFields.map((f) => (
+            <div key={f.label}>
+              <Label className="text-muted-foreground">{f.label}</Label>
+              <div className="mt-1 font-medium whitespace-pre-wrap">{f.render(d)}</div>
+            </div>
+          ))}
+          <div>
+            <Label className="text-muted-foreground">Ngày tạo</Label>
+            <div className="mt-1 text-xs">{formatDateTime(d.createdAt)}</div>
+          </div>
+        </div>
+      </div>
+
+      {/* Section 2: Quy trình duyệt */}
+      <div className="rounded-lg border bg-card p-6 space-y-3">
+        <h3 className="font-semibold text-base">2. Quy trình duyệt</h3>
+        <div className="grid grid-cols-1 md:grid-cols-2 gap-3 text-sm">
+          <div>
+            <Label className="text-muted-foreground">Quy trình</Label>
+            <div className="mt-1 text-xs">
+              {d.workflowCode ? (
+                <>
+                  <span className="font-mono">{d.workflowCode}</span> - {d.workflowName}
+                </>
+              ) : '— Chưa chọn —'}
+            </div>
+          </div>
+          <div>
+            <Label className="text-muted-foreground">Cấp hiện tại</Label>
+            <div className="mt-1 font-medium">{d.currentApprovalLevelOrder ?? '—'}</div>
+          </div>
+        </div>
+      </div>
+
+      {/* Section 3: Ý kiến cấp duyệt V2 dynamic */}
+      <div className="rounded-lg border bg-card p-6 space-y-3">
+        <h3 className="font-semibold text-base">3. Ý kiến cấp duyệt</h3>
+        {d.levelOpinions.length === 0 ? (
+          <div className="text-sm text-muted-foreground">Chưa có ý kiến.</div>
+        ) : (
+          <div className="space-y-3">
+            {[...d.levelOpinions]
+              .sort((a, b) =>
+                (a.stepOrder ?? 0) - (b.stepOrder ?? 0) ||
+                (a.levelOrder ?? 0) - (b.levelOrder ?? 0))
+              .map((o) => (
+                <div key={o.id} className="rounded border-l-4 border-emerald-400 bg-emerald-50/40 p-3">
+                  <div className="flex items-center justify-between text-xs text-muted-foreground">
+                    <span>
+                      Bước {o.stepOrder} {o.stepName} · Cấp {o.levelOrder}
+                    </span>
+                    <span>{formatDateTime(o.signedAt)}</span>
+                  </div>
+                  <div className="mt-1 font-medium">{o.signedByFullName}</div>
+                  <div className="mt-1 whitespace-pre-wrap text-sm">{o.comment ?? '(duyệt — không ý kiến)'}</div>
+                </div>
+              ))}
+          </div>
+        )}
+      </div>
+
+      {/* Action confirm dialog */}
+      <Dialog
+        open={!!actionDialog}
+        onClose={() => {
+          setActionDialog(null)
+          setComment('')
+        }}
+        title={actionDialog ? `${ACTION_LABEL[actionDialog].text} đơn từ` : ''}
+      >
+        <div className="space-y-3">
+          <Label htmlFor="action-comment">Ý kiến (tuỳ chọn)</Label>
+          <Textarea
+            id="action-comment"
+            value={comment}
+            onChange={(e) => setComment(e.target.value)}
+            rows={4}
+            placeholder="Để trống nếu không có ý kiến..."
+            maxLength={2000}
+          />
+          <div className="text-xs text-muted-foreground">{comment.length}/2000</div>
+          <div className="flex justify-end gap-2 pt-2">
+            <Button variant="outline" onClick={() => setActionDialog(null)}>
+              Huỷ
+            </Button>
+            <Button
+              onClick={() => actionDialog && action.mutate(actionDialog)}
+              disabled={action.isPending}
+              className={actionDialog ? ACTION_LABEL[actionDialog].tone : ''}
+            >
+              {action.isPending ? 'Đang xử lý...' : 'Xác nhận'}
+            </Button>
+          </div>
+        </div>
+      </Dialog>
+    </div>
+  )
+}
--- a/fe-admin/src/pages/office/WorkflowAppsListPage.tsx
+++ b/fe-admin/src/pages/office/WorkflowAppsListPage.tsx
@ -1,9 +1,9 @@
 // Generic Workflow Apps List Page — Phase 10.3 G-O4+G-O5+G-O6 (S38 2026-05-28).
-// SKELETON Phase 1: read-only list. Create form + workflow actions DEFER Phase 11.
+// Wave 3a (S42 2026-05-30): row click → Detail page (workflow actions + opinion timeline).
 // Handles 4 module via URL `:kind` param: leave / ot / travel / vehicle.
 // File MIRROR SHA256 identical fe-user counterpart.
 import { useQuery } from '@tanstack/react-query'
-import { useParams } from 'react-router-dom'
+import { useNavigate, useParams } from 'react-router-dom'
 import { CalendarOff, Clock, Plane, Car, FileSignature } from 'lucide-react'
 import { PageHeader } from '@/components/PageHeader'
 import { api } from '@/lib/api'
@ -80,6 +80,7 @@ const ICON_MAP: Record<Kind, any> = {

 export function WorkflowAppsListPage() {
  const { kind = 'leave' } = useParams<{ kind: Kind }>()
+  const navigate = useNavigate()
  const config = KIND_CONFIG[kind as Kind]
  const Icon = ICON_MAP[kind as Kind] ?? FileSignature

@ -99,11 +100,6 @@ export function WorkflowAppsListPage() {
    <div className="space-y-4">
      <PageHeader title={config.title} description={config.description} />

-      <div className="rounded-lg border bg-amber-50/50 p-3 text-sm text-amber-900">
-        ⚠️ <strong>Skeleton Phase 1 (S38):</strong> Read-only list. Form tạo + workflow Approve/Reject defer Phase 11 polish.
-        Em chủ trì kích hoạt full ApproveV2 wire khi anh main yêu cầu.
-      </div>
-
      <div className="rounded-lg border bg-card">
        <table className="w-full text-sm">
          <thead className="border-b bg-muted/50">
@ -131,7 +127,11 @@ export function WorkflowAppsListPage() {
              </tr>
            )}
            {items.map((item: any) => (
-              <tr key={item.id} className="border-b">
+              <tr
+                key={item.id}
+                className="border-b cursor-pointer hover:bg-muted/40"
+                onClick={() => navigate(`/workflow-apps/${kind}/${item.id}`)}
+              >
                {config.columns.map((c) => (
                  <td key={c.key} className="px-4 py-2">{c.render(item)}</td>
                ))}
--- a/fe-admin/src/types/workflowApps.ts
+++ b/fe-admin/src/types/workflowApps.ts
@ -43,6 +43,59 @@ export const IT_TICKET_STATUS_LABELS: Record<number, string> = {
  1: 'Mới', 2: 'Đang xử lý', 3: 'Đã giải quyết', 4: 'Đã đóng', 5: 'Mở lại',
 }

+// Phase 11 P11-A Wave 3a (S42 2026-05-30) — Detail + LevelOpinion shape cho 4 module
+// (leave/ot/travel/vehicle) mirror BE LeaveOt/TravelVehicleApprovalFeatures DetailDto.
+export interface WorkflowAppLevelOpinion {
+  id: string
+  approvalWorkflowLevelId: string
+  stepOrder: number | null
+  stepName: string | null
+  levelOrder: number | null
+  approverUserId: string | null
+  comment: string | null
+  signedAt: string
+  signedByUserId: string
+  signedByFullName: string
+}
+
+// Superset detail — module-specific fields optional, rendered theo KIND_CONFIG.detailFields.
+export interface WorkflowAppDetail {
+  id: string
+  maDonTu: string | null
+  requesterUserId: string
+  requesterFullName: string
+  status: number
+  approvalWorkflowId: string | null
+  workflowCode: string | null
+  workflowName: string | null
+  currentApprovalLevelOrder: number | null
+  rejectedFromStatus: number | null
+  createdAt: string
+  levelOpinions: WorkflowAppLevelOpinion[]
+  // leave
+  leaveTypeId?: string
+  startDate?: string
+  endDate?: string
+  numDays?: number
+  reason?: string
+  // ot
+  otDate?: string
+  startTime?: string
+  endTime?: string
+  hours?: number
+  otPolicyId?: string | null
+  // travel
+  destination?: string
+  purpose?: string
+  estimatedCost?: number | null
+  // vehicle
+  vehicleLicense?: string
+  vehicleName?: string | null
+  startAt?: string
+  endAt?: string
+  driverName?: string | null
+}
+
 export interface PagedResult<T> {
  items: T[]
  total: number
--- a/fe-user/src/App.tsx
+++ b/fe-user/src/App.tsx
@ -29,6 +29,7 @@ import { ProposalCreatePage } from '@/pages/office/ProposalCreatePage'
 import { ProposalDetailPage } from '@/pages/office/ProposalDetailPage'
 import { ProposalsListPage } from '@/pages/office/ProposalsListPage'
 import { WorkflowAppsListPage } from '@/pages/office/WorkflowAppsListPage'
+import { WorkflowAppDetailPage } from '@/pages/office/WorkflowAppDetailPage'
 import { ItTicketsPage } from '@/pages/office/ItTicketsPage'
 import { MyAttendancePage } from '@/pages/office/MyAttendancePage'
 import { HrmDashboardPage } from '@/pages/hrm/HrmDashboardPage'
@ -79,6 +80,7 @@ function App() {
            <Route path="/proposals/new" element={<ProposalCreatePage />} />
            <Route path="/proposals/:id" element={<ProposalDetailPage />} />
            <Route path="/workflow-apps/:kind" element={<WorkflowAppsListPage />} />
+            <Route path="/workflow-apps/:kind/:id" element={<WorkflowAppDetailPage />} />
            <Route path="/it-tickets" element={<ItTicketsPage />} />
            <Route path="/attendance" element={<MyAttendancePage />} />
            <Route path="/hr/dashboard" element={<HrmDashboardPage />} />
--- a/fe-user/src/pages/office/WorkflowAppDetailPage.tsx
+++ b/fe-user/src/pages/office/WorkflowAppDetailPage.tsx
@ -0,0 +1,423 @@
+// Generic Workflow App Detail page — Phase 11 P11-A Wave 3a (S42 2026-05-30).
+// Declarative KIND_CONFIG Record<Kind> mirror WorkflowAppsListPage — 4 module
+// leave / ot / travel / vehicle. Workflow status + Ý kiến cấp duyệt timeline +
+// Submit/Approve/Reject/Return actions (mirror ProposalDetailPage cấu trúc).
+// File MIRROR SHA256 identical với fe-user counterpart.
+import { useState } from 'react'
+import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query'
+import { useNavigate, useParams } from 'react-router-dom'
+import {
+  ArrowLeft, Ban, CalendarOff, Car, CheckCircle2, Clock, Plane, RotateCcw, Send,
+} from 'lucide-react'
+import { toast } from 'sonner'
+import { PageHeader } from '@/components/PageHeader'
+import { Button } from '@/components/ui/Button'
+import { Dialog } from '@/components/ui/Dialog'
+import { Label } from '@/components/ui/Label'
+import { Textarea } from '@/components/ui/Textarea'
+import { api } from '@/lib/api'
+import { getErrorMessage } from '@/lib/apiError'
+import { cn } from '@/lib/cn'
+import {
+  WORKFLOW_APP_STATUS_BADGE, WORKFLOW_APP_STATUS_LABELS,
+  WorkflowAppStatus, type WorkflowAppDetail,
+} from '@/types/workflowApps'
+
+type Kind = 'leave' | 'ot' | 'travel' | 'vehicle'
+type ActionKind = 'approve' | 'reject' | 'return'
+
+interface WorkflowOption { id: string; code: string; name: string }
+
+function formatDate(iso?: string): string {
+  if (!iso) return '—'
+  return new Date(iso).toLocaleDateString('vi-VN')
+}
+
+function formatDateTime(iso?: string): string {
+  if (!iso) return '—'
+  return new Date(iso).toLocaleString('vi-VN')
+}
+
+function formatVnd(n: number | null | undefined): string {
+  if (n === null || n === undefined) return '—'
+  return n.toLocaleString('vi-VN') + ' đ'
+}
+
+const ACTION_LABEL: Record<ActionKind, { text: string; tone: string }> = {
+  approve: { text: 'Duyệt', tone: 'bg-emerald-600 hover:bg-emerald-700' },
+  reject: { text: 'Từ chối', tone: 'bg-red-600 hover:bg-red-700' },
+  return: { text: 'Trả lại', tone: 'bg-orange-600 hover:bg-orange-700' },
+}
+
+const KIND_CONFIG: Record<Kind, {
+  title: string
+  endpoint: string
+  applicableType: number
+  icon: any
+  detailFields: Array<{ label: string; render: (x: WorkflowAppDetail) => React.ReactNode }>
+}> = {
+  leave: {
+    title: 'Đơn xin nghỉ phép',
+    endpoint: '/leave-requests',
+    applicableType: 5,
+    icon: CalendarOff,
+    detailFields: [
+      { label: 'Người xin', render: (x) => x.requesterFullName },
+      { label: 'Từ ngày', render: (x) => formatDate(x.startDate) },
+      { label: 'Đến ngày', render: (x) => formatDate(x.endDate) },
+      { label: 'Số ngày', render: (x) => x.numDays ?? '—' },
+      { label: 'Lý do', render: (x) => x.reason || '—' },
+    ],
+  },
+  ot: {
+    title: 'Đơn đăng ký OT',
+    endpoint: '/ot-requests',
+    applicableType: 6,
+    icon: Clock,
+    detailFields: [
+      { label: 'Người xin', render: (x) => x.requesterFullName },
+      { label: 'Ngày OT', render: (x) => formatDate(x.otDate) },
+      { label: 'Giờ bắt đầu', render: (x) => x.startTime ?? '—' },
+      { label: 'Giờ kết thúc', render: (x) => x.endTime ?? '—' },
+      { label: 'Số giờ', render: (x) => x.hours ?? '—' },
+      { label: 'Lý do', render: (x) => x.reason || '—' },
+    ],
+  },
+  travel: {
+    title: 'Đơn đi công tác',
+    endpoint: '/travel-requests',
+    applicableType: 9,
+    icon: Plane,
+    detailFields: [
+      { label: 'Người xin', render: (x) => x.requesterFullName },
+      { label: 'Địa điểm', render: (x) => x.destination || '—' },
+      { label: 'Từ ngày', render: (x) => formatDate(x.startDate) },
+      { label: 'Đến ngày', render: (x) => formatDate(x.endDate) },
+      { label: 'Số ngày', render: (x) => x.numDays ?? '—' },
+      { label: 'Dự toán chi phí', render: (x) => formatVnd(x.estimatedCost) },
+      { label: 'Mục đích', render: (x) => x.purpose || '—' },
+    ],
+  },
+  vehicle: {
+    title: 'Đặt xe công',
+    endpoint: '/vehicle-bookings',
+    applicableType: 7,
+    icon: Car,
+    detailFields: [
+      { label: 'Người đặt', render: (x) => x.requesterFullName },
+      { label: 'Biển số', render: (x) => <span className="font-mono">{x.vehicleLicense ?? '—'}</span> },
+      { label: 'Tên xe', render: (x) => x.vehicleName || '—' },
+      { label: 'Bắt đầu', render: (x) => formatDateTime(x.startAt) },
+      { label: 'Kết thúc', render: (x) => formatDateTime(x.endAt) },
+      { label: 'Địa điểm đến', render: (x) => x.destination || '—' },
+      { label: 'Tài xế', render: (x) => x.driverName || '—' },
+      { label: 'Mục đích', render: (x) => x.purpose || '—' },
+    ],
+  },
+}
+
+export function WorkflowAppDetailPage() {
+  const { kind = 'leave', id } = useParams<{ kind: Kind; id: string }>()
+  const navigate = useNavigate()
+  const qc = useQueryClient()
+  const config = KIND_CONFIG[kind as Kind]
+
+  const [actionDialog, setActionDialog] = useState<ActionKind | null>(null)
+  const [comment, setComment] = useState('')
+  const [pickedWorkflowId, setPickedWorkflowId] = useState<string>('')
+
+  const detail = useQuery({
+    queryKey: [config?.endpoint, id],
+    queryFn: async () =>
+      (await api.get<WorkflowAppDetail>(`${config.endpoint}/${id}`)).data,
+    enabled: !!config && !!id,
+  })
+
+  const d = detail.data
+  const status = d?.status
+  const isDraft = status === WorkflowAppStatus.Nhap || status === WorkflowAppStatus.TraLai
+  const isInWorkflow = status === WorkflowAppStatus.DaGuiDuyet
+  const hasWorkflow = !!d?.approvalWorkflowId
+
+  // Workflow picker — chỉ fetch khi draft chưa pin workflow.
+  const workflows = useQuery({
+    queryKey: ['approval-workflows-v2', { applicableType: config?.applicableType, isUserSelectable: true }],
+    queryFn: async () =>
+      (await api.get<WorkflowOption[]>('/approval-workflows-v2', {
+        params: { applicableType: config.applicableType, isUserSelectable: true },
+      })).data,
+    enabled: !!config && isDraft && !hasWorkflow,
+  })
+
+  const invalidate = () => {
+    qc.invalidateQueries({ queryKey: [config.endpoint, id] })
+    qc.invalidateQueries({ queryKey: [config.endpoint] })
+  }
+
+  const pinWorkflow = useMutation({
+    mutationFn: async (workflowId: string) => {
+      await api.put(`${config.endpoint}/${id}`, { approvalWorkflowId: workflowId })
+    },
+    onSuccess: () => {
+      toast.success('Đã chọn quy trình duyệt')
+      invalidate()
+    },
+    onError: (e) => toast.error(getErrorMessage(e)),
+  })
+
+  const submit = useMutation({
+    mutationFn: async () => {
+      await api.post(`${config.endpoint}/${id}/submit`, {})
+    },
+    onSuccess: () => {
+      toast.success('Đã gửi duyệt')
+      invalidate()
+    },
+    onError: (e) => toast.error(getErrorMessage(e)),
+  })
+
+  const action = useMutation({
+    mutationFn: async (k: ActionKind) => {
+      await api.post(`${config.endpoint}/${id}/${k}`, { comment: comment.trim() || null })
+    },
+    onSuccess: (_, k) => {
+      toast.success(`Đã ${ACTION_LABEL[k].text.toLowerCase()}`)
+      setActionDialog(null)
+      setComment('')
+      invalidate()
+    },
+    onError: (e) => toast.error(getErrorMessage(e)),
+  })
+
+  if (!config) {
+    return <div className="text-red-600">Module không tồn tại: {kind}</div>
+  }
+
+  if (detail.isLoading) {
+    return (
+      <div className="space-y-4">
+        <PageHeader title="Đang tải..." />
+      </div>
+    )
+  }
+
+  if (detail.isError || !d) {
+    return (
+      <div className="space-y-4">
+        <PageHeader
+          title="Lỗi"
+          actions={
+            <Button variant="outline" onClick={() => navigate(`/workflow-apps/${kind}`)}>
+              <ArrowLeft className="mr-2 h-4 w-4" />
+              Quay lại
+            </Button>
+          }
+        />
+        <div className="rounded-lg border bg-red-50 p-4 text-sm text-red-800">
+          Không tải được dữ liệu đơn từ.
+        </div>
+      </div>
+    )
+  }
+
+  const Icon = config.icon
+
+  return (
+    <div className="space-y-4">
+      <PageHeader
+        title={d.maDonTu ?? '(Chưa có mã)'}
+        description={config.title}
+        actions={
+          <Button variant="outline" onClick={() => navigate(`/workflow-apps/${kind}`)}>
+            <ArrowLeft className="mr-2 h-4 w-4" />
+            Danh sách
+          </Button>
+        }
+      />
+
+      {/* Status row + action buttons */}
+      <div className="flex flex-wrap items-center justify-between gap-3 rounded-lg border bg-card p-4">
+        <div className="flex items-center gap-3">
+          <span
+            className={cn(
+              'inline-flex items-center rounded-md border px-3 py-1 text-sm font-medium',
+              WORKFLOW_APP_STATUS_BADGE[d.status],
+            )}
+          >
+            {WORKFLOW_APP_STATUS_LABELS[d.status]}
+          </span>
+          {d.currentApprovalLevelOrder != null && (
+            <span className="text-sm text-muted-foreground">
+              Cấp hiện tại: <span className="font-semibold">{d.currentApprovalLevelOrder}</span>
+            </span>
+          )}
+          {d.workflowCode && (
+            <span className="text-sm text-muted-foreground">
+              Quy trình: <span className="font-mono">{d.workflowCode}</span>
+            </span>
+          )}
+        </div>
+        <div className="flex flex-wrap items-center gap-2">
+          {isDraft && !hasWorkflow && (
+            <>
+              <select
+                className="h-9 rounded-md border bg-background px-2 text-sm"
+                value={pickedWorkflowId}
+                onChange={(e) => setPickedWorkflowId(e.target.value)}
+              >
+                <option value="">— Chọn quy trình duyệt —</option>
+                {(workflows.data ?? []).map((w) => (
+                  <option key={w.id} value={w.id}>
+                    {w.code} - {w.name}
+                  </option>
+                ))}
+              </select>
+              <Button
+                variant="outline"
+                disabled={!pickedWorkflowId || pinWorkflow.isPending}
+                onClick={() => pickedWorkflowId && pinWorkflow.mutate(pickedWorkflowId)}
+              >
+                Lưu quy trình
+              </Button>
+            </>
+          )}
+          {isDraft && (
+            <Button
+              onClick={() => submit.mutate()}
+              disabled={submit.isPending || !hasWorkflow}
+              title={!hasWorkflow ? 'Cần chọn quy trình duyệt trước khi gửi' : undefined}
+            >
+              <Send className="mr-2 h-4 w-4" />
+              {status === WorkflowAppStatus.TraLai ? 'Gửi duyệt lại' : 'Gửi duyệt'}
+            </Button>
+          )}
+          {isInWorkflow && (
+            <>
+              <Button onClick={() => setActionDialog('approve')} className={ACTION_LABEL.approve.tone}>
+                <CheckCircle2 className="mr-2 h-4 w-4" />
+                Duyệt
+              </Button>
+              <Button onClick={() => setActionDialog('return')} className={ACTION_LABEL.return.tone}>
+                <RotateCcw className="mr-2 h-4 w-4" />
+                Trả lại
+              </Button>
+              <Button onClick={() => setActionDialog('reject')} className={ACTION_LABEL.reject.tone}>
+                <Ban className="mr-2 h-4 w-4" />
+                Từ chối
+              </Button>
+            </>
+          )}
+        </div>
+      </div>
+
+      {isDraft && !hasWorkflow && (
+        <div className="rounded-lg border bg-amber-50/50 p-3 text-sm text-amber-900">
+          Đơn chưa gắn quy trình duyệt. Vui lòng chọn quy trình rồi bấm <strong>Lưu quy trình</strong> trước khi gửi duyệt.
+        </div>
+      )}
+
+      {/* Section 1: Thông tin */}
+      <div className="rounded-lg border bg-card p-6 space-y-3">
+        <h3 className="flex items-center gap-2 font-semibold text-base">
+          <Icon className="h-4 w-4 opacity-70" />
+          1. Thông tin
+        </h3>
+        <div className="grid grid-cols-1 md:grid-cols-2 gap-3 text-sm">
+          {config.detailFields.map((f) => (
+            <div key={f.label}>
+              <Label className="text-muted-foreground">{f.label}</Label>
+              <div className="mt-1 font-medium whitespace-pre-wrap">{f.render(d)}</div>
+            </div>
+          ))}
+          <div>
+            <Label className="text-muted-foreground">Ngày tạo</Label>
+            <div className="mt-1 text-xs">{formatDateTime(d.createdAt)}</div>
+          </div>
+        </div>
+      </div>
+
+      {/* Section 2: Quy trình duyệt */}
+      <div className="rounded-lg border bg-card p-6 space-y-3">
+        <h3 className="font-semibold text-base">2. Quy trình duyệt</h3>
+        <div className="grid grid-cols-1 md:grid-cols-2 gap-3 text-sm">
+          <div>
+            <Label className="text-muted-foreground">Quy trình</Label>
+            <div className="mt-1 text-xs">
+              {d.workflowCode ? (
+                <>
+                  <span className="font-mono">{d.workflowCode}</span> - {d.workflowName}
+                </>
+              ) : '— Chưa chọn —'}
+            </div>
+          </div>
+          <div>
+            <Label className="text-muted-foreground">Cấp hiện tại</Label>
+            <div className="mt-1 font-medium">{d.currentApprovalLevelOrder ?? '—'}</div>
+          </div>
+        </div>
+      </div>
+
+      {/* Section 3: Ý kiến cấp duyệt V2 dynamic */}
+      <div className="rounded-lg border bg-card p-6 space-y-3">
+        <h3 className="font-semibold text-base">3. Ý kiến cấp duyệt</h3>
+        {d.levelOpinions.length === 0 ? (
+          <div className="text-sm text-muted-foreground">Chưa có ý kiến.</div>
+        ) : (
+          <div className="space-y-3">
+            {[...d.levelOpinions]
+              .sort((a, b) =>
+                (a.stepOrder ?? 0) - (b.stepOrder ?? 0) ||
+                (a.levelOrder ?? 0) - (b.levelOrder ?? 0))
+              .map((o) => (
+                <div key={o.id} className="rounded border-l-4 border-emerald-400 bg-emerald-50/40 p-3">
+                  <div className="flex items-center justify-between text-xs text-muted-foreground">
+                    <span>
+                      Bước {o.stepOrder} {o.stepName} · Cấp {o.levelOrder}
+                    </span>
+                    <span>{formatDateTime(o.signedAt)}</span>
+                  </div>
+                  <div className="mt-1 font-medium">{o.signedByFullName}</div>
+                  <div className="mt-1 whitespace-pre-wrap text-sm">{o.comment ?? '(duyệt — không ý kiến)'}</div>
+                </div>
+              ))}
+          </div>
+        )}
+      </div>
+
+      {/* Action confirm dialog */}
+      <Dialog
+        open={!!actionDialog}
+        onClose={() => {
+          setActionDialog(null)
+          setComment('')
+        }}
+        title={actionDialog ? `${ACTION_LABEL[actionDialog].text} đơn từ` : ''}
+      >
+        <div className="space-y-3">
+          <Label htmlFor="action-comment">Ý kiến (tuỳ chọn)</Label>
+          <Textarea
+            id="action-comment"
+            value={comment}
+            onChange={(e) => setComment(e.target.value)}
+            rows={4}
+            placeholder="Để trống nếu không có ý kiến..."
+            maxLength={2000}
+          />
+          <div className="text-xs text-muted-foreground">{comment.length}/2000</div>
+          <div className="flex justify-end gap-2 pt-2">
+            <Button variant="outline" onClick={() => setActionDialog(null)}>
+              Huỷ
+            </Button>
+            <Button
+              onClick={() => actionDialog && action.mutate(actionDialog)}
+              disabled={action.isPending}
+              className={actionDialog ? ACTION_LABEL[actionDialog].tone : ''}
+            >
+              {action.isPending ? 'Đang xử lý...' : 'Xác nhận'}
+            </Button>
+          </div>
+        </div>
+      </Dialog>
+    </div>
+  )
+}
--- a/fe-user/src/pages/office/WorkflowAppsListPage.tsx
+++ b/fe-user/src/pages/office/WorkflowAppsListPage.tsx
@ -1,9 +1,9 @@
 // Generic Workflow Apps List Page — Phase 10.3 G-O4+G-O5+G-O6 (S38 2026-05-28).
-// SKELETON Phase 1: read-only list. Create form + workflow actions DEFER Phase 11.
+// Wave 3a (S42 2026-05-30): row click → Detail page (workflow actions + opinion timeline).
 // Handles 4 module via URL `:kind` param: leave / ot / travel / vehicle.
 // File MIRROR SHA256 identical fe-user counterpart.
 import { useQuery } from '@tanstack/react-query'
-import { useParams } from 'react-router-dom'
+import { useNavigate, useParams } from 'react-router-dom'
 import { CalendarOff, Clock, Plane, Car, FileSignature } from 'lucide-react'
 import { PageHeader } from '@/components/PageHeader'
 import { api } from '@/lib/api'
@ -80,6 +80,7 @@ const ICON_MAP: Record<Kind, any> = {

 export function WorkflowAppsListPage() {
  const { kind = 'leave' } = useParams<{ kind: Kind }>()
+  const navigate = useNavigate()
  const config = KIND_CONFIG[kind as Kind]
  const Icon = ICON_MAP[kind as Kind] ?? FileSignature

@ -99,11 +100,6 @@ export function WorkflowAppsListPage() {
    <div className="space-y-4">
      <PageHeader title={config.title} description={config.description} />

-      <div className="rounded-lg border bg-amber-50/50 p-3 text-sm text-amber-900">
-        ⚠️ <strong>Skeleton Phase 1 (S38):</strong> Read-only list. Form tạo + workflow Approve/Reject defer Phase 11 polish.
-        Em chủ trì kích hoạt full ApproveV2 wire khi anh main yêu cầu.
-      </div>
-
      <div className="rounded-lg border bg-card">
        <table className="w-full text-sm">
          <thead className="border-b bg-muted/50">
@ -131,7 +127,11 @@ export function WorkflowAppsListPage() {
              </tr>
            )}
            {items.map((item: any) => (
-              <tr key={item.id} className="border-b">
+              <tr
+                key={item.id}
+                className="border-b cursor-pointer hover:bg-muted/40"
+                onClick={() => navigate(`/workflow-apps/${kind}/${item.id}`)}
+              >
                {config.columns.map((c) => (
                  <td key={c.key} className="px-4 py-2">{c.render(item)}</td>
                ))}
--- a/fe-user/src/types/workflowApps.ts
+++ b/fe-user/src/types/workflowApps.ts
@ -43,6 +43,59 @@ export const IT_TICKET_STATUS_LABELS: Record<number, string> = {
  1: 'Mới', 2: 'Đang xử lý', 3: 'Đã giải quyết', 4: 'Đã đóng', 5: 'Mở lại',
 }

+// Phase 11 P11-A Wave 3a (S42 2026-05-30) — Detail + LevelOpinion shape cho 4 module
+// (leave/ot/travel/vehicle) mirror BE LeaveOt/TravelVehicleApprovalFeatures DetailDto.
+export interface WorkflowAppLevelOpinion {
+  id: string
+  approvalWorkflowLevelId: string
+  stepOrder: number | null
+  stepName: string | null
+  levelOrder: number | null
+  approverUserId: string | null
+  comment: string | null
+  signedAt: string
+  signedByUserId: string
+  signedByFullName: string
+}
+
+// Superset detail — module-specific fields optional, rendered theo KIND_CONFIG.detailFields.
+export interface WorkflowAppDetail {
+  id: string
+  maDonTu: string | null
+  requesterUserId: string
+  requesterFullName: string
+  status: number
+  approvalWorkflowId: string | null
+  workflowCode: string | null
+  workflowName: string | null
+  currentApprovalLevelOrder: number | null
+  rejectedFromStatus: number | null
+  createdAt: string
+  levelOpinions: WorkflowAppLevelOpinion[]
+  // leave
+  leaveTypeId?: string
+  startDate?: string
+  endDate?: string
+  numDays?: number
+  reason?: string
+  // ot
+  otDate?: string
+  startTime?: string
+  endTime?: string
+  hours?: number
+  otPolicyId?: string | null
+  // travel
+  destination?: string
+  purpose?: string
+  estimatedCost?: number | null
+  // vehicle
+  vehicleLicense?: string
+  vehicleName?: string | null
+  startAt?: string
+  endAt?: string
+  driverName?: string | null
+}
+
 export interface PagedResult<T> {
  items: T[]
  total: number
--- a/src/Backend/SolutionErp.Api/Controllers/LeaveRequestsController.cs
+++ b/src/Backend/SolutionErp.Api/Controllers/LeaveRequestsController.cs
@ -14,10 +14,63 @@ public class LeaveRequestsController(IMediator mediator) : ControllerBase
    public async Task<IActionResult> GetList([FromQuery] int? status, [FromQuery] Guid? requesterUserId, [FromQuery] int page = 1, [FromQuery] int pageSize = 50)
        => Ok(await mediator.Send(new GetLeaveRequestsQuery(status, requesterUserId, page, pageSize)));

+    [HttpGet("{id:guid}")]
+    public async Task<IActionResult> GetById(Guid id)
+    {
+        var dto = await mediator.Send(new GetLeaveRequestByIdQuery(id));
+        return dto is null ? NotFound() : Ok(dto);
+    }
+
    [HttpPost]
    public async Task<IActionResult> Create([FromBody] CreateLeaveRequestCommand cmd)
    {
        var id = await mediator.Send(cmd);
-        return Created(string.Empty, new { id });
+        return CreatedAtAction(nameof(GetById), new { id }, new { id });
    }
+
+    [HttpPut("{id:guid}")]
+    public async Task<IActionResult> Update(Guid id, [FromBody] UpdateLeaveRequestDraftBody body)
+    {
+        await mediator.Send(new UpdateLeaveRequestDraftCommand(id, body.LeaveTypeId, body.StartDate,
+            body.EndDate, body.NumDays, body.Reason, body.ApprovalWorkflowId));
+        return NoContent();
+    }
+
+    [HttpPost("{id:guid}/submit")]
+    public async Task<IActionResult> Submit(Guid id)
+    {
+        await mediator.Send(new SubmitLeaveRequestCommand(id));
+        return NoContent();
+    }
+
+    [HttpPost("{id:guid}/approve")]
+    public async Task<IActionResult> Approve(Guid id, [FromBody] WorkflowActionBody body)
+    {
+        await mediator.Send(new ApproveLeaveRequestCommand(id, body.Comment));
+        return NoContent();
+    }
+
+    [HttpPost("{id:guid}/reject")]
+    public async Task<IActionResult> Reject(Guid id, [FromBody] WorkflowActionBody body)
+    {
+        await mediator.Send(new RejectLeaveRequestCommand(id, body.Comment));
+        return NoContent();
+    }
+
+    [HttpPost("{id:guid}/return")]
+    public async Task<IActionResult> Return(Guid id, [FromBody] WorkflowActionBody body)
+    {
+        await mediator.Send(new ReturnLeaveRequestCommand(id, body.Comment));
+        return NoContent();
+    }
+
+    public record UpdateLeaveRequestDraftBody(
+        Guid LeaveTypeId,
+        DateTime StartDate,
+        DateTime EndDate,
+        decimal NumDays,
+        string Reason,
+        Guid? ApprovalWorkflowId);
+
+    public record WorkflowActionBody(string? Comment);
 }
--- a/src/Backend/SolutionErp.Api/Controllers/OtRequestsController.cs
+++ b/src/Backend/SolutionErp.Api/Controllers/OtRequestsController.cs
@ -14,10 +14,64 @@ public class OtRequestsController(IMediator mediator) : ControllerBase
    public async Task<IActionResult> GetList([FromQuery] int? status, [FromQuery] Guid? requesterUserId, [FromQuery] int page = 1, [FromQuery] int pageSize = 50)
        => Ok(await mediator.Send(new GetOtRequestsQuery(status, requesterUserId, page, pageSize)));

+    [HttpGet("{id:guid}")]
+    public async Task<IActionResult> GetById(Guid id)
+    {
+        var dto = await mediator.Send(new GetOtRequestByIdQuery(id));
+        return dto is null ? NotFound() : Ok(dto);
+    }
+
    [HttpPost]
    public async Task<IActionResult> Create([FromBody] CreateOtRequestCommand cmd)
    {
        var id = await mediator.Send(cmd);
-        return Created(string.Empty, new { id });
+        return CreatedAtAction(nameof(GetById), new { id }, new { id });
    }
+
+    [HttpPut("{id:guid}")]
+    public async Task<IActionResult> Update(Guid id, [FromBody] UpdateOtRequestDraftBody body)
+    {
+        await mediator.Send(new UpdateOtRequestDraftCommand(id, body.OtDate, body.StartTime,
+            body.EndTime, body.Hours, body.Reason, body.OtPolicyId, body.ApprovalWorkflowId));
+        return NoContent();
+    }
+
+    [HttpPost("{id:guid}/submit")]
+    public async Task<IActionResult> Submit(Guid id)
+    {
+        await mediator.Send(new SubmitOtRequestCommand(id));
+        return NoContent();
+    }
+
+    [HttpPost("{id:guid}/approve")]
+    public async Task<IActionResult> Approve(Guid id, [FromBody] WorkflowActionBody body)
+    {
+        await mediator.Send(new ApproveOtRequestCommand(id, body.Comment));
+        return NoContent();
+    }
+
+    [HttpPost("{id:guid}/reject")]
+    public async Task<IActionResult> Reject(Guid id, [FromBody] WorkflowActionBody body)
+    {
+        await mediator.Send(new RejectOtRequestCommand(id, body.Comment));
+        return NoContent();
+    }
+
+    [HttpPost("{id:guid}/return")]
+    public async Task<IActionResult> Return(Guid id, [FromBody] WorkflowActionBody body)
+    {
+        await mediator.Send(new ReturnOtRequestCommand(id, body.Comment));
+        return NoContent();
+    }
+
+    public record UpdateOtRequestDraftBody(
+        DateTime OtDate,
+        TimeSpan StartTime,
+        TimeSpan EndTime,
+        decimal Hours,
+        string Reason,
+        Guid? OtPolicyId,
+        Guid? ApprovalWorkflowId);
+
+    public record WorkflowActionBody(string? Comment);
 }
--- a/src/Backend/SolutionErp.Api/Controllers/TravelRequestsController.cs
+++ b/src/Backend/SolutionErp.Api/Controllers/TravelRequestsController.cs
@ -14,10 +14,64 @@ public class TravelRequestsController(IMediator mediator) : ControllerBase
    public async Task<IActionResult> GetList([FromQuery] int? status, [FromQuery] Guid? requesterUserId, [FromQuery] int page = 1, [FromQuery] int pageSize = 50)
        => Ok(await mediator.Send(new GetTravelRequestsQuery(status, requesterUserId, page, pageSize)));

+    [HttpGet("{id:guid}")]
+    public async Task<IActionResult> GetById(Guid id)
+    {
+        var dto = await mediator.Send(new GetTravelRequestByIdQuery(id));
+        return dto is null ? NotFound() : Ok(dto);
+    }
+
    [HttpPost]
    public async Task<IActionResult> Create([FromBody] CreateTravelRequestCommand cmd)
    {
        var id = await mediator.Send(cmd);
-        return Created(string.Empty, new { id });
+        return CreatedAtAction(nameof(GetById), new { id }, new { id });
    }
+
+    [HttpPut("{id:guid}")]
+    public async Task<IActionResult> Update(Guid id, [FromBody] UpdateTravelRequestBody body)
+    {
+        await mediator.Send(new UpdateTravelRequestDraftCommand(id, body.Destination, body.StartDate,
+            body.EndDate, body.NumDays, body.Purpose, body.EstimatedCost, body.ApprovalWorkflowId));
+        return NoContent();
+    }
+
+    [HttpPost("{id:guid}/submit")]
+    public async Task<IActionResult> Submit(Guid id)
+    {
+        await mediator.Send(new SubmitTravelRequestCommand(id));
+        return NoContent();
+    }
+
+    [HttpPost("{id:guid}/approve")]
+    public async Task<IActionResult> Approve(Guid id, [FromBody] ApprovalActionBody body)
+    {
+        await mediator.Send(new ApproveTravelRequestCommand(id, body.Comment));
+        return NoContent();
+    }
+
+    [HttpPost("{id:guid}/reject")]
+    public async Task<IActionResult> Reject(Guid id, [FromBody] ApprovalActionBody body)
+    {
+        await mediator.Send(new RejectTravelRequestCommand(id, body.Comment));
+        return NoContent();
+    }
+
+    [HttpPost("{id:guid}/return")]
+    public async Task<IActionResult> Return(Guid id, [FromBody] ApprovalActionBody body)
+    {
+        await mediator.Send(new ReturnTravelRequestCommand(id, body.Comment));
+        return NoContent();
+    }
+
+    public record UpdateTravelRequestBody(
+        string Destination,
+        DateTime StartDate,
+        DateTime EndDate,
+        int NumDays,
+        string Purpose,
+        decimal? EstimatedCost,
+        Guid? ApprovalWorkflowId);
+
+    public record ApprovalActionBody(string? Comment);
 }
--- a/src/Backend/SolutionErp.Api/Controllers/VehicleBookingsController.cs
+++ b/src/Backend/SolutionErp.Api/Controllers/VehicleBookingsController.cs
@ -14,10 +14,65 @@ public class VehicleBookingsController(IMediator mediator) : ControllerBase
    public async Task<IActionResult> GetList([FromQuery] int? status, [FromQuery] Guid? requesterUserId, [FromQuery] int page = 1, [FromQuery] int pageSize = 50)
        => Ok(await mediator.Send(new GetVehicleBookingsQuery(status, requesterUserId, page, pageSize)));

+    [HttpGet("{id:guid}")]
+    public async Task<IActionResult> GetById(Guid id)
+    {
+        var dto = await mediator.Send(new GetVehicleBookingByIdQuery(id));
+        return dto is null ? NotFound() : Ok(dto);
+    }
+
    [HttpPost]
    public async Task<IActionResult> Create([FromBody] CreateVehicleBookingCommand cmd)
    {
        var id = await mediator.Send(cmd);
-        return Created(string.Empty, new { id });
+        return CreatedAtAction(nameof(GetById), new { id }, new { id });
    }
+
+    [HttpPut("{id:guid}")]
+    public async Task<IActionResult> Update(Guid id, [FromBody] UpdateVehicleBookingBody body)
+    {
+        await mediator.Send(new UpdateVehicleBookingDraftCommand(id, body.VehicleLicense, body.VehicleName,
+            body.StartAt, body.EndAt, body.Destination, body.Purpose, body.DriverName, body.ApprovalWorkflowId));
+        return NoContent();
+    }
+
+    [HttpPost("{id:guid}/submit")]
+    public async Task<IActionResult> Submit(Guid id)
+    {
+        await mediator.Send(new SubmitVehicleBookingCommand(id));
+        return NoContent();
+    }
+
+    [HttpPost("{id:guid}/approve")]
+    public async Task<IActionResult> Approve(Guid id, [FromBody] ApprovalActionBody body)
+    {
+        await mediator.Send(new ApproveVehicleBookingCommand(id, body.Comment));
+        return NoContent();
+    }
+
+    [HttpPost("{id:guid}/reject")]
+    public async Task<IActionResult> Reject(Guid id, [FromBody] ApprovalActionBody body)
+    {
+        await mediator.Send(new RejectVehicleBookingCommand(id, body.Comment));
+        return NoContent();
+    }
+
+    [HttpPost("{id:guid}/return")]
+    public async Task<IActionResult> Return(Guid id, [FromBody] ApprovalActionBody body)
+    {
+        await mediator.Send(new ReturnVehicleBookingCommand(id, body.Comment));
+        return NoContent();
+    }
+
+    public record UpdateVehicleBookingBody(
+        string VehicleLicense,
+        string? VehicleName,
+        DateTime StartAt,
+        DateTime EndAt,
+        string Destination,
+        string Purpose,
+        string? DriverName,
+        Guid? ApprovalWorkflowId);
+
+    public record ApprovalActionBody(string? Comment);
 }
--- a/src/Backend/SolutionErp.Application/Common/Interfaces/IApplicationDbContext.cs
+++ b/src/Backend/SolutionErp.Application/Common/Interfaces/IApplicationDbContext.cs
@ -128,6 +128,14 @@ public interface IApplicationDbContext
    DbSet<VehicleBooking> VehicleBookings { get; }
    DbSet<ItTicket> ItTickets { get; }

+    // Phase 11 P11-A (Mig 41) — Wire ApproveV2 + LevelOpinions cho 4 WorkflowApps
+    // module (cookie-cutter mirror Proposal Mig 38). + shared atomic codegen MaDonTu.
+    DbSet<LeaveRequestLevelOpinion> LeaveRequestLevelOpinions { get; }
+    DbSet<OtRequestLevelOpinion> OtRequestLevelOpinions { get; }
+    DbSet<TravelRequestLevelOpinion> TravelRequestLevelOpinions { get; }
+    DbSet<VehicleBookingLevelOpinion> VehicleBookingLevelOpinions { get; }
+    DbSet<WorkflowAppCodeSequence> WorkflowAppCodeSequences { get; }
+
    // Phase 10.4 G-P1 (Mig 40 — S38) — Chấm công web GPS.
    DbSet<Attendance> Attendances { get; }

--- a/src/Backend/SolutionErp.Application/Office/LeaveOtApprovalFeatures.cs
+++ b/src/Backend/SolutionErp.Application/Office/LeaveOtApprovalFeatures.cs
@ -0,0 +1,749 @@
+using System.Data;
+using FluentValidation;
+using MediatR;
+using Microsoft.EntityFrameworkCore;
+using SolutionErp.Application.Common.Exceptions;
+using SolutionErp.Application.Common.Interfaces;
+using SolutionErp.Domain.ApprovalWorkflowsV2;
+using SolutionErp.Domain.Office;
+
+namespace SolutionErp.Application.Office;
+
+// Phase 11 P11-A Wave 2a (S41/S42 2026-05-30) — wire ApproveV2 CQRS cho LeaveRequest + OtRequest.
+// Cookie-cutter mirror ProposalFeatures Region 2 (Mig 38). Schema sẵn (Mig 41).
+// ApplicableType: LeaveRequest=5, OtRequest=6.
+//
+// Per module 7 handler: GetById detail · UpdateDraft · Submit · Approve(UPSERT+advance) ·
+//   Reject(TuChoi) · Return(TraLai). 1 static helper GenerateMaDonTuAsync dùng chung.
+//
+// CONSTRAINT: KHÔNG sửa WorkflowAppsFeatures.cs (Region 1 Create/List ở đó). KHÔNG đụng
+//   Travel/Vehicle (Wave 2b song song). MaDonTu gen lần Submit đầu (null→gen).
+
+// ===== Shared CodeGen helper (dùng chung Leave + Ot trong file này) =====
+
+internal static class WorkflowAppCodeGen
+{
+    // Mirror ProposalFeatures.GenerateMaDeXuatAsync — Serializable tx + Prefix-keyed sequence.
+    // Format: "{prefix}/{seq:D3}" — prefix vd "DT/LR/2026" → "DT/LR/2026/001".
+    internal static async Task<string> GenerateMaDonTuAsync(
+        IApplicationDbContext db, string prefix, int year, IDateTime clock, CancellationToken ct)
+    {
+        var fullPrefix = $"{prefix}/{year}";
+        var dbContext = (DbContext)db;
+        await using var tx = await dbContext.Database.BeginTransactionAsync(IsolationLevel.Serializable, ct);
+        var seq = await db.WorkflowAppCodeSequences.FirstOrDefaultAsync(s => s.Prefix == fullPrefix, ct);
+        if (seq is null)
+        {
+            seq = new WorkflowAppCodeSequence { Prefix = fullPrefix, LastSeq = 0, UpdatedAt = clock.UtcNow };
+            db.WorkflowAppCodeSequences.Add(seq);
+        }
+        seq.LastSeq++;
+        seq.UpdatedAt = clock.UtcNow;
+        await db.SaveChangesAsync(ct);
+        await tx.CommitAsync(ct);
+        return $"{fullPrefix}/{seq.LastSeq:D3}";
+    }
+}
+
+// =========================================================================
+// MODULE A: LeaveRequest (ApplicableType=5, prefix "DT/LR")
+// =========================================================================
+
+public record LeaveRequestLevelOpinionDto(
+    Guid Id,
+    Guid ApprovalWorkflowLevelId,
+    int? StepOrder,
+    string? StepName,
+    int? LevelOrder,
+    Guid? ApproverUserId,
+    string? Comment,
+    DateTime SignedAt,
+    Guid SignedByUserId,
+    string SignedByFullName);
+
+public record LeaveRequestDetailDto(
+    Guid Id,
+    string? MaDonTu,
+    Guid RequesterUserId,
+    string RequesterFullName,
+    Guid LeaveTypeId,
+    DateTime StartDate,
+    DateTime EndDate,
+    decimal NumDays,
+    string Reason,
+    int Status,
+    Guid? ApprovalWorkflowId,
+    string? WorkflowCode,
+    string? WorkflowName,
+    int? CurrentApprovalLevelOrder,
+    int? RejectedFromStatus,
+    DateTime CreatedAt,
+    List<LeaveRequestLevelOpinionDto> LevelOpinions);
+
+public record GetLeaveRequestByIdQuery(Guid Id) : IRequest<LeaveRequestDetailDto?>;
+
+public class GetLeaveRequestByIdHandler(IApplicationDbContext db)
+    : IRequestHandler<GetLeaveRequestByIdQuery, LeaveRequestDetailDto?>
+{
+    public async Task<LeaveRequestDetailDto?> Handle(GetLeaveRequestByIdQuery req, CancellationToken ct)
+    {
+        var p = await db.LeaveRequests.AsNoTracking()
+            .Include(x => x.LevelOpinions)
+            .FirstOrDefaultAsync(x => x.Id == req.Id && !x.IsDeleted, ct);
+        if (p is null) return null;
+
+        string? wfCode = null;
+        string? wfName = null;
+        if (p.ApprovalWorkflowId.HasValue)
+        {
+            var wf = await db.ApprovalWorkflows.AsNoTracking()
+                .Where(w => w.Id == p.ApprovalWorkflowId.Value)
+                .Select(w => new { w.Code, w.Name })
+                .FirstOrDefaultAsync(ct);
+            wfCode = wf?.Code;
+            wfName = wf?.Name;
+        }
+
+        var levelIds = p.LevelOpinions.Select(o => o.ApprovalWorkflowLevelId).Distinct().ToList();
+        var levels = await db.ApprovalWorkflowSteps.AsNoTracking()
+            .Where(s => s.Levels.Any(l => levelIds.Contains(l.Id)))
+            .Select(s => new
+            {
+                s.Id,
+                s.Order,
+                s.Name,
+                Levels = s.Levels.Where(l => levelIds.Contains(l.Id))
+                    .Select(l => new { l.Id, l.Order, l.ApproverUserId })
+                    .ToList(),
+            })
+            .ToListAsync(ct);
+
+        var levelLookup = levels.SelectMany(s => s.Levels.Select(l => new { Step = s, Level = l }))
+            .ToDictionary(x => x.Level.Id);
+
+        var opinions = p.LevelOpinions
+            .Select(o =>
+            {
+                levelLookup.TryGetValue(o.ApprovalWorkflowLevelId, out var lvl);
+                return new LeaveRequestLevelOpinionDto(
+                    o.Id,
+                    o.ApprovalWorkflowLevelId,
+                    lvl?.Step.Order,
+                    lvl?.Step.Name,
+                    lvl?.Level.Order,
+                    lvl?.Level.ApproverUserId,
+                    o.Comment,
+                    o.SignedAt,
+                    o.SignedByUserId,
+                    o.SignedByFullName);
+            })
+            .OrderBy(o => o.StepOrder).ThenBy(o => o.LevelOrder)
+            .ToList();
+
+        return new LeaveRequestDetailDto(
+            p.Id, p.MaDonTu, p.RequesterUserId, p.RequesterFullName, p.LeaveTypeId,
+            p.StartDate, p.EndDate, p.NumDays, p.Reason, (int)p.Status,
+            p.ApprovalWorkflowId, wfCode, wfName, p.CurrentApprovalLevelOrder,
+            p.RejectedFromStatus.HasValue ? (int)p.RejectedFromStatus.Value : (int?)null,
+            p.CreatedAt, opinions);
+    }
+}
+
+public record UpdateLeaveRequestDraftCommand(
+    Guid Id,
+    Guid LeaveTypeId,
+    DateTime StartDate,
+    DateTime EndDate,
+    decimal NumDays,
+    string Reason,
+    Guid? ApprovalWorkflowId) : IRequest;
+
+public class UpdateLeaveRequestDraftValidator : AbstractValidator<UpdateLeaveRequestDraftCommand>
+{
+    public UpdateLeaveRequestDraftValidator()
+    {
+        RuleFor(x => x.Reason).NotEmpty().MaximumLength(1000);
+        RuleFor(x => x.NumDays).GreaterThan(0);
+        RuleFor(x => x.EndDate).GreaterThanOrEqualTo(x => x.StartDate);
+    }
+}
+
+public class UpdateLeaveRequestDraftHandler(IApplicationDbContext db, ICurrentUser cu, IDateTime clock)
+    : IRequestHandler<UpdateLeaveRequestDraftCommand>
+{
+    public async Task Handle(UpdateLeaveRequestDraftCommand req, CancellationToken ct)
+    {
+        var p = await db.LeaveRequests.FirstOrDefaultAsync(x => x.Id == req.Id && !x.IsDeleted, ct);
+        if (p is null) throw new NotFoundException("LeaveRequest", req.Id);
+
+        var isOwner = p.RequesterUserId == cu.UserId;
+        var isAdmin = cu.Roles.Contains("Admin");
+        if (!isOwner && !isAdmin)
+            throw new ForbiddenException("Chỉ người tạo hoặc Admin được sửa đơn.");
+        if (p.Status != WorkflowAppStatus.Nhap && p.Status != WorkflowAppStatus.TraLai)
+            throw new ConflictException("Chỉ sửa được khi trạng thái Nháp hoặc Trả lại.");
+
+        if (req.ApprovalWorkflowId.HasValue && req.ApprovalWorkflowId != p.ApprovalWorkflowId)
+        {
+            var wfType = await db.ApprovalWorkflows.AsNoTracking()
+                .Where(w => w.Id == req.ApprovalWorkflowId.Value)
+                .Select(w => (int?)w.ApplicableType)
+                .FirstOrDefaultAsync(ct);
+            if (wfType is null)
+                throw new NotFoundException("ApprovalWorkflow", req.ApprovalWorkflowId.Value);
+            if (wfType.Value != (int)ApprovalWorkflowApplicableType.LeaveRequest)
+                throw new ConflictException("Quy trình duyệt không thuộc loại Đơn nghỉ phép.");
+        }
+
+        p.LeaveTypeId = req.LeaveTypeId;
+        p.StartDate = req.StartDate;
+        p.EndDate = req.EndDate;
+        p.NumDays = req.NumDays;
+        p.Reason = req.Reason.Trim();
+        p.ApprovalWorkflowId = req.ApprovalWorkflowId;
+        p.UpdatedAt = clock.UtcNow;
+        p.UpdatedBy = cu.UserId;
+        await db.SaveChangesAsync(ct);
+    }
+}
+
+public record SubmitLeaveRequestCommand(Guid Id) : IRequest;
+
+public class SubmitLeaveRequestHandler(IApplicationDbContext db, ICurrentUser cu, IDateTime clock)
+    : IRequestHandler<SubmitLeaveRequestCommand>
+{
+    public async Task Handle(SubmitLeaveRequestCommand req, CancellationToken ct)
+    {
+        var p = await db.LeaveRequests.FirstOrDefaultAsync(x => x.Id == req.Id && !x.IsDeleted, ct);
+        if (p is null) throw new NotFoundException("LeaveRequest", req.Id);
+
+        var isOwner = p.RequesterUserId == cu.UserId;
+        var isAdmin = cu.Roles.Contains("Admin");
+        if (!isOwner && !isAdmin)
+            throw new ForbiddenException("Chỉ người tạo hoặc Admin được gửi duyệt.");
+        if (p.Status != WorkflowAppStatus.Nhap && p.Status != WorkflowAppStatus.TraLai)
+            throw new ConflictException("Chỉ gửi duyệt được khi trạng thái Nháp hoặc Trả lại.");
+        if (!p.ApprovalWorkflowId.HasValue)
+            throw new ConflictException("Chưa chọn quy trình duyệt.");
+
+        var wfType = await db.ApprovalWorkflows.AsNoTracking()
+            .Where(w => w.Id == p.ApprovalWorkflowId.Value)
+            .Select(w => (int?)w.ApplicableType)
+            .FirstOrDefaultAsync(ct);
+        if (wfType is null)
+            throw new NotFoundException("ApprovalWorkflow", p.ApprovalWorkflowId.Value);
+        if (wfType.Value != (int)ApprovalWorkflowApplicableType.LeaveRequest)
+            throw new ConflictException("Quy trình duyệt không thuộc loại Đơn nghỉ phép.");
+
+        if (string.IsNullOrEmpty(p.MaDonTu))
+            p.MaDonTu = await WorkflowAppCodeGen.GenerateMaDonTuAsync(db, "DT/LR", clock.Now.Year, clock, ct);
+
+        p.Status = WorkflowAppStatus.DaGuiDuyet;
+        p.CurrentApprovalLevelOrder = 1;
+        p.RejectedFromStatus = null;
+        p.UpdatedAt = clock.UtcNow;
+        p.UpdatedBy = cu.UserId;
+        await db.SaveChangesAsync(ct);
+    }
+}
+
+public record ApproveLeaveRequestCommand(Guid Id, string? Comment) : IRequest;
+
+public class ApproveLeaveRequestHandler(IApplicationDbContext db, ICurrentUser cu, IDateTime clock)
+    : IRequestHandler<ApproveLeaveRequestCommand>
+{
+    public async Task Handle(ApproveLeaveRequestCommand req, CancellationToken ct)
+    {
+        if (cu.UserId is null) throw new UnauthorizedException();
+
+        var p = await db.LeaveRequests.FirstOrDefaultAsync(x => x.Id == req.Id && !x.IsDeleted, ct);
+        if (p is null) throw new NotFoundException("LeaveRequest", req.Id);
+        if (p.Status != WorkflowAppStatus.DaGuiDuyet)
+            throw new ConflictException("Chỉ duyệt được khi trạng thái Đã gửi duyệt.");
+        if (!p.ApprovalWorkflowId.HasValue || !p.CurrentApprovalLevelOrder.HasValue)
+            throw new ConflictException("Quy trình duyệt chưa pin hoặc thiếu cấp hiện tại.");
+
+        var wf = await db.ApprovalWorkflows.AsNoTracking()
+            .Include(w => w.Steps).ThenInclude(s => s.Levels)
+            .FirstOrDefaultAsync(w => w.Id == p.ApprovalWorkflowId.Value, ct);
+        if (wf is null) throw new NotFoundException("ApprovalWorkflow", p.ApprovalWorkflowId.Value);
+
+        var allLevels = wf.Steps.OrderBy(s => s.Order)
+            .SelectMany(s => s.Levels.OrderBy(l => l.Order).Select(l => new { Step = s, Level = l }))
+            .ToList();
+        if (allLevels.Count == 0)
+            throw new ConflictException("Quy trình duyệt không có cấp duyệt.");
+
+        var currentSlot = allLevels.ElementAtOrDefault(p.CurrentApprovalLevelOrder.Value - 1);
+        if (currentSlot is null)
+            throw new ConflictException($"Cấp duyệt {p.CurrentApprovalLevelOrder.Value} không tồn tại trong quy trình.");
+
+        var isAdmin = cu.Roles.Contains("Admin");
+        if (!isAdmin && currentSlot.Level.ApproverUserId != cu.UserId.Value)
+            throw new ForbiddenException("Không phải người duyệt của cấp này.");
+
+        var existing = await db.LeaveRequestLevelOpinions
+            .FirstOrDefaultAsync(o => o.LeaveRequestId == p.Id && o.ApprovalWorkflowLevelId == currentSlot.Level.Id, ct);
+        var commentFinal = string.IsNullOrWhiteSpace(req.Comment)
+            ? "(duyệt — không ý kiến)"
+            : req.Comment.Trim();
+        if (existing is null)
+        {
+            db.LeaveRequestLevelOpinions.Add(new LeaveRequestLevelOpinion
+            {
+                LeaveRequestId = p.Id,
+                ApprovalWorkflowLevelId = currentSlot.Level.Id,
+                Comment = commentFinal,
+                SignedAt = clock.UtcNow,
+                SignedByUserId = cu.UserId.Value,
+                SignedByFullName = cu.FullName ?? "(unknown)",
+                CreatedAt = clock.UtcNow,
+                CreatedBy = cu.UserId,
+            });
+        }
+        else
+        {
+            existing.Comment = commentFinal;
+            existing.SignedAt = clock.UtcNow;
+            existing.SignedByUserId = cu.UserId.Value;
+            existing.SignedByFullName = cu.FullName ?? "(unknown)";
+            existing.UpdatedAt = clock.UtcNow;
+            existing.UpdatedBy = cu.UserId;
+        }
+
+        if (p.CurrentApprovalLevelOrder.Value < allLevels.Count)
+        {
+            p.CurrentApprovalLevelOrder = p.CurrentApprovalLevelOrder.Value + 1;
+        }
+        else
+        {
+            p.Status = WorkflowAppStatus.DaDuyet;
+            p.CurrentApprovalLevelOrder = null;
+        }
+        p.UpdatedAt = clock.UtcNow;
+        p.UpdatedBy = cu.UserId;
+        await db.SaveChangesAsync(ct);
+    }
+}
+
+public record RejectLeaveRequestCommand(Guid Id, string? Comment) : IRequest;
+
+public class RejectLeaveRequestHandler(IApplicationDbContext db, ICurrentUser cu, IDateTime clock)
+    : IRequestHandler<RejectLeaveRequestCommand>
+{
+    public async Task Handle(RejectLeaveRequestCommand req, CancellationToken ct)
+    {
+        var p = await db.LeaveRequests.FirstOrDefaultAsync(x => x.Id == req.Id && !x.IsDeleted, ct);
+        if (p is null) throw new NotFoundException("LeaveRequest", req.Id);
+        if (p.Status != WorkflowAppStatus.DaGuiDuyet)
+            throw new ConflictException("Chỉ từ chối được khi đang trong workflow duyệt.");
+
+        var isAdmin = cu.Roles.Contains("Admin");
+        if (!isAdmin && p.CurrentApprovalLevelOrder.HasValue && p.ApprovalWorkflowId.HasValue)
+        {
+            var wf = await db.ApprovalWorkflows.AsNoTracking()
+                .Include(w => w.Steps).ThenInclude(s => s.Levels)
+                .FirstOrDefaultAsync(w => w.Id == p.ApprovalWorkflowId.Value, ct);
+            var allLevels = wf?.Steps.OrderBy(s => s.Order)
+                .SelectMany(s => s.Levels.OrderBy(l => l.Order))
+                .ToList() ?? new();
+            var currentLevel = allLevels.ElementAtOrDefault(p.CurrentApprovalLevelOrder.Value - 1);
+            if (currentLevel?.ApproverUserId != cu.UserId)
+                throw new ForbiddenException("Không phải người duyệt của cấp này.");
+        }
+
+        p.Status = WorkflowAppStatus.TuChoi;
+        p.CurrentApprovalLevelOrder = null;
+        p.UpdatedAt = clock.UtcNow;
+        p.UpdatedBy = cu.UserId;
+        await db.SaveChangesAsync(ct);
+    }
+}
+
+public record ReturnLeaveRequestCommand(Guid Id, string? Comment) : IRequest;
+
+public class ReturnLeaveRequestHandler(IApplicationDbContext db, ICurrentUser cu, IDateTime clock)
+    : IRequestHandler<ReturnLeaveRequestCommand>
+{
+    public async Task Handle(ReturnLeaveRequestCommand req, CancellationToken ct)
+    {
+        var p = await db.LeaveRequests.FirstOrDefaultAsync(x => x.Id == req.Id && !x.IsDeleted, ct);
+        if (p is null) throw new NotFoundException("LeaveRequest", req.Id);
+        if (p.Status != WorkflowAppStatus.DaGuiDuyet)
+            throw new ConflictException("Chỉ trả lại được khi đang trong workflow duyệt.");
+
+        var isAdmin = cu.Roles.Contains("Admin");
+        if (!isAdmin && p.CurrentApprovalLevelOrder.HasValue && p.ApprovalWorkflowId.HasValue)
+        {
+            var wf = await db.ApprovalWorkflows.AsNoTracking()
+                .Include(w => w.Steps).ThenInclude(s => s.Levels)
+                .FirstOrDefaultAsync(w => w.Id == p.ApprovalWorkflowId.Value, ct);
+            var allLevels = wf?.Steps.OrderBy(s => s.Order)
+                .SelectMany(s => s.Levels.OrderBy(l => l.Order))
+                .ToList() ?? new();
+            var currentLevel = allLevels.ElementAtOrDefault(p.CurrentApprovalLevelOrder.Value - 1);
+            if (currentLevel?.ApproverUserId != cu.UserId)
+                throw new ForbiddenException("Không phải người duyệt của cấp này.");
+        }
+
+        p.Status = WorkflowAppStatus.TraLai;
+        p.RejectedFromStatus = WorkflowAppStatus.DaGuiDuyet;
+        p.CurrentApprovalLevelOrder = null;
+        p.UpdatedAt = clock.UtcNow;
+        p.UpdatedBy = cu.UserId;
+        await db.SaveChangesAsync(ct);
+    }
+}
+
+// =========================================================================
+// MODULE B: OtRequest (ApplicableType=6, prefix "DT/OT")
+// =========================================================================
+
+public record OtRequestLevelOpinionDto(
+    Guid Id,
+    Guid ApprovalWorkflowLevelId,
+    int? StepOrder,
+    string? StepName,
+    int? LevelOrder,
+    Guid? ApproverUserId,
+    string? Comment,
+    DateTime SignedAt,
+    Guid SignedByUserId,
+    string SignedByFullName);
+
+public record OtRequestDetailDto(
+    Guid Id,
+    string? MaDonTu,
+    Guid RequesterUserId,
+    string RequesterFullName,
+    DateTime OtDate,
+    TimeSpan StartTime,
+    TimeSpan EndTime,
+    decimal Hours,
+    string Reason,
+    Guid? OtPolicyId,
+    int Status,
+    Guid? ApprovalWorkflowId,
+    string? WorkflowCode,
+    string? WorkflowName,
+    int? CurrentApprovalLevelOrder,
+    int? RejectedFromStatus,
+    DateTime CreatedAt,
+    List<OtRequestLevelOpinionDto> LevelOpinions);
+
+public record GetOtRequestByIdQuery(Guid Id) : IRequest<OtRequestDetailDto?>;
+
+public class GetOtRequestByIdHandler(IApplicationDbContext db)
+    : IRequestHandler<GetOtRequestByIdQuery, OtRequestDetailDto?>
+{
+    public async Task<OtRequestDetailDto?> Handle(GetOtRequestByIdQuery req, CancellationToken ct)
+    {
+        var p = await db.OtRequests.AsNoTracking()
+            .Include(x => x.LevelOpinions)
+            .FirstOrDefaultAsync(x => x.Id == req.Id && !x.IsDeleted, ct);
+        if (p is null) return null;
+
+        string? wfCode = null;
+        string? wfName = null;
+        if (p.ApprovalWorkflowId.HasValue)
+        {
+            var wf = await db.ApprovalWorkflows.AsNoTracking()
+                .Where(w => w.Id == p.ApprovalWorkflowId.Value)
+                .Select(w => new { w.Code, w.Name })
+                .FirstOrDefaultAsync(ct);
+            wfCode = wf?.Code;
+            wfName = wf?.Name;
+        }
+
+        var levelIds = p.LevelOpinions.Select(o => o.ApprovalWorkflowLevelId).Distinct().ToList();
+        var levels = await db.ApprovalWorkflowSteps.AsNoTracking()
+            .Where(s => s.Levels.Any(l => levelIds.Contains(l.Id)))
+            .Select(s => new
+            {
+                s.Id,
+                s.Order,
+                s.Name,
+                Levels = s.Levels.Where(l => levelIds.Contains(l.Id))
+                    .Select(l => new { l.Id, l.Order, l.ApproverUserId })
+                    .ToList(),
+            })
+            .ToListAsync(ct);
+
+        var levelLookup = levels.SelectMany(s => s.Levels.Select(l => new { Step = s, Level = l }))
+            .ToDictionary(x => x.Level.Id);
+
+        var opinions = p.LevelOpinions
+            .Select(o =>
+            {
+                levelLookup.TryGetValue(o.ApprovalWorkflowLevelId, out var lvl);
+                return new OtRequestLevelOpinionDto(
+                    o.Id,
+                    o.ApprovalWorkflowLevelId,
+                    lvl?.Step.Order,
+                    lvl?.Step.Name,
+                    lvl?.Level.Order,
+                    lvl?.Level.ApproverUserId,
+                    o.Comment,
+                    o.SignedAt,
+                    o.SignedByUserId,
+                    o.SignedByFullName);
+            })
+            .OrderBy(o => o.StepOrder).ThenBy(o => o.LevelOrder)
+            .ToList();
+
+        return new OtRequestDetailDto(
+            p.Id, p.MaDonTu, p.RequesterUserId, p.RequesterFullName,
+            p.OtDate, p.StartTime, p.EndTime, p.Hours, p.Reason, p.OtPolicyId, (int)p.Status,
+            p.ApprovalWorkflowId, wfCode, wfName, p.CurrentApprovalLevelOrder,
+            p.RejectedFromStatus.HasValue ? (int)p.RejectedFromStatus.Value : (int?)null,
+            p.CreatedAt, opinions);
+    }
+}
+
+public record UpdateOtRequestDraftCommand(
+    Guid Id,
+    DateTime OtDate,
+    TimeSpan StartTime,
+    TimeSpan EndTime,
+    decimal Hours,
+    string Reason,
+    Guid? OtPolicyId,
+    Guid? ApprovalWorkflowId) : IRequest;
+
+public class UpdateOtRequestDraftValidator : AbstractValidator<UpdateOtRequestDraftCommand>
+{
+    public UpdateOtRequestDraftValidator()
+    {
+        RuleFor(x => x.Reason).NotEmpty().MaximumLength(1000);
+        RuleFor(x => x.Hours).GreaterThan(0);
+        RuleFor(x => x.EndTime).GreaterThan(x => x.StartTime);
+    }
+}
+
+public class UpdateOtRequestDraftHandler(IApplicationDbContext db, ICurrentUser cu, IDateTime clock)
+    : IRequestHandler<UpdateOtRequestDraftCommand>
+{
+    public async Task Handle(UpdateOtRequestDraftCommand req, CancellationToken ct)
+    {
+        var p = await db.OtRequests.FirstOrDefaultAsync(x => x.Id == req.Id && !x.IsDeleted, ct);
+        if (p is null) throw new NotFoundException("OtRequest", req.Id);
+
+        var isOwner = p.RequesterUserId == cu.UserId;
+        var isAdmin = cu.Roles.Contains("Admin");
+        if (!isOwner && !isAdmin)
+            throw new ForbiddenException("Chỉ người tạo hoặc Admin được sửa đơn.");
+        if (p.Status != WorkflowAppStatus.Nhap && p.Status != WorkflowAppStatus.TraLai)
+            throw new ConflictException("Chỉ sửa được khi trạng thái Nháp hoặc Trả lại.");
+
+        if (req.ApprovalWorkflowId.HasValue && req.ApprovalWorkflowId != p.ApprovalWorkflowId)
+        {
+            var wfType = await db.ApprovalWorkflows.AsNoTracking()
+                .Where(w => w.Id == req.ApprovalWorkflowId.Value)
+                .Select(w => (int?)w.ApplicableType)
+                .FirstOrDefaultAsync(ct);
+            if (wfType is null)
+                throw new NotFoundException("ApprovalWorkflow", req.ApprovalWorkflowId.Value);
+            if (wfType.Value != (int)ApprovalWorkflowApplicableType.OtRequest)
+                throw new ConflictException("Quy trình duyệt không thuộc loại Đơn OT.");
+        }
+
+        p.OtDate = req.OtDate;
+        p.StartTime = req.StartTime;
+        p.EndTime = req.EndTime;
+        p.Hours = req.Hours;
+        p.Reason = req.Reason.Trim();
+        p.OtPolicyId = req.OtPolicyId;
+        p.ApprovalWorkflowId = req.ApprovalWorkflowId;
+        p.UpdatedAt = clock.UtcNow;
+        p.UpdatedBy = cu.UserId;
+        await db.SaveChangesAsync(ct);
+    }
+}
+
+public record SubmitOtRequestCommand(Guid Id) : IRequest;
+
+public class SubmitOtRequestHandler(IApplicationDbContext db, ICurrentUser cu, IDateTime clock)
+    : IRequestHandler<SubmitOtRequestCommand>
+{
+    public async Task Handle(SubmitOtRequestCommand req, CancellationToken ct)
+    {
+        var p = await db.OtRequests.FirstOrDefaultAsync(x => x.Id == req.Id && !x.IsDeleted, ct);
+        if (p is null) throw new NotFoundException("OtRequest", req.Id);
+
+        var isOwner = p.RequesterUserId == cu.UserId;
+        var isAdmin = cu.Roles.Contains("Admin");
+        if (!isOwner && !isAdmin)
+            throw new ForbiddenException("Chỉ người tạo hoặc Admin được gửi duyệt.");
+        if (p.Status != WorkflowAppStatus.Nhap && p.Status != WorkflowAppStatus.TraLai)
+            throw new ConflictException("Chỉ gửi duyệt được khi trạng thái Nháp hoặc Trả lại.");
+        if (!p.ApprovalWorkflowId.HasValue)
+            throw new ConflictException("Chưa chọn quy trình duyệt.");
+
+        var wfType = await db.ApprovalWorkflows.AsNoTracking()
+            .Where(w => w.Id == p.ApprovalWorkflowId.Value)
+            .Select(w => (int?)w.ApplicableType)
+            .FirstOrDefaultAsync(ct);
+        if (wfType is null)
+            throw new NotFoundException("ApprovalWorkflow", p.ApprovalWorkflowId.Value);
+        if (wfType.Value != (int)ApprovalWorkflowApplicableType.OtRequest)
+            throw new ConflictException("Quy trình duyệt không thuộc loại Đơn OT.");
+
+        if (string.IsNullOrEmpty(p.MaDonTu))
+            p.MaDonTu = await WorkflowAppCodeGen.GenerateMaDonTuAsync(db, "DT/OT", clock.Now.Year, clock, ct);
+
+        p.Status = WorkflowAppStatus.DaGuiDuyet;
+        p.CurrentApprovalLevelOrder = 1;
+        p.RejectedFromStatus = null;
+        p.UpdatedAt = clock.UtcNow;
+        p.UpdatedBy = cu.UserId;
+        await db.SaveChangesAsync(ct);
+    }
+}
+
+public record ApproveOtRequestCommand(Guid Id, string? Comment) : IRequest;
+
+public class ApproveOtRequestHandler(IApplicationDbContext db, ICurrentUser cu, IDateTime clock)
+    : IRequestHandler<ApproveOtRequestCommand>
+{
+    public async Task Handle(ApproveOtRequestCommand req, CancellationToken ct)
+    {
+        if (cu.UserId is null) throw new UnauthorizedException();
+
+        var p = await db.OtRequests.FirstOrDefaultAsync(x => x.Id == req.Id && !x.IsDeleted, ct);
+        if (p is null) throw new NotFoundException("OtRequest", req.Id);
+        if (p.Status != WorkflowAppStatus.DaGuiDuyet)
+            throw new ConflictException("Chỉ duyệt được khi trạng thái Đã gửi duyệt.");
+        if (!p.ApprovalWorkflowId.HasValue || !p.CurrentApprovalLevelOrder.HasValue)
+            throw new ConflictException("Quy trình duyệt chưa pin hoặc thiếu cấp hiện tại.");
+
+        var wf = await db.ApprovalWorkflows.AsNoTracking()
+            .Include(w => w.Steps).ThenInclude(s => s.Levels)
+            .FirstOrDefaultAsync(w => w.Id == p.ApprovalWorkflowId.Value, ct);
+        if (wf is null) throw new NotFoundException("ApprovalWorkflow", p.ApprovalWorkflowId.Value);
+
+        var allLevels = wf.Steps.OrderBy(s => s.Order)
+            .SelectMany(s => s.Levels.OrderBy(l => l.Order).Select(l => new { Step = s, Level = l }))
+            .ToList();
+        if (allLevels.Count == 0)
+            throw new ConflictException("Quy trình duyệt không có cấp duyệt.");
+
+        var currentSlot = allLevels.ElementAtOrDefault(p.CurrentApprovalLevelOrder.Value - 1);
+        if (currentSlot is null)
+            throw new ConflictException($"Cấp duyệt {p.CurrentApprovalLevelOrder.Value} không tồn tại trong quy trình.");
+
+        var isAdmin = cu.Roles.Contains("Admin");
+        if (!isAdmin && currentSlot.Level.ApproverUserId != cu.UserId.Value)
+            throw new ForbiddenException("Không phải người duyệt của cấp này.");
+
+        var existing = await db.OtRequestLevelOpinions
+            .FirstOrDefaultAsync(o => o.OtRequestId == p.Id && o.ApprovalWorkflowLevelId == currentSlot.Level.Id, ct);
+        var commentFinal = string.IsNullOrWhiteSpace(req.Comment)
+            ? "(duyệt — không ý kiến)"
+            : req.Comment.Trim();
+        if (existing is null)
+        {
+            db.OtRequestLevelOpinions.Add(new OtRequestLevelOpinion
+            {
+                OtRequestId = p.Id,
+                ApprovalWorkflowLevelId = currentSlot.Level.Id,
+                Comment = commentFinal,
+                SignedAt = clock.UtcNow,
+                SignedByUserId = cu.UserId.Value,
+                SignedByFullName = cu.FullName ?? "(unknown)",
+                CreatedAt = clock.UtcNow,
+                CreatedBy = cu.UserId,
+            });
+        }
+        else
+        {
+            existing.Comment = commentFinal;
+            existing.SignedAt = clock.UtcNow;
+            existing.SignedByUserId = cu.UserId.Value;
+            existing.SignedByFullName = cu.FullName ?? "(unknown)";
+            existing.UpdatedAt = clock.UtcNow;
+            existing.UpdatedBy = cu.UserId;
+        }
+
+        if (p.CurrentApprovalLevelOrder.Value < allLevels.Count)
+        {
+            p.CurrentApprovalLevelOrder = p.CurrentApprovalLevelOrder.Value + 1;
+        }
+        else
+        {
+            p.Status = WorkflowAppStatus.DaDuyet;
+            p.CurrentApprovalLevelOrder = null;
+        }
+        p.UpdatedAt = clock.UtcNow;
+        p.UpdatedBy = cu.UserId;
+        await db.SaveChangesAsync(ct);
+    }
+}
+
+public record RejectOtRequestCommand(Guid Id, string? Comment) : IRequest;
+
+public class RejectOtRequestHandler(IApplicationDbContext db, ICurrentUser cu, IDateTime clock)
+    : IRequestHandler<RejectOtRequestCommand>
+{
+    public async Task Handle(RejectOtRequestCommand req, CancellationToken ct)
+    {
+        var p = await db.OtRequests.FirstOrDefaultAsync(x => x.Id == req.Id && !x.IsDeleted, ct);
+        if (p is null) throw new NotFoundException("OtRequest", req.Id);
+        if (p.Status != WorkflowAppStatus.DaGuiDuyet)
+            throw new ConflictException("Chỉ từ chối được khi đang trong workflow duyệt.");
+
+        var isAdmin = cu.Roles.Contains("Admin");
+        if (!isAdmin && p.CurrentApprovalLevelOrder.HasValue && p.ApprovalWorkflowId.HasValue)
+        {
+            var wf = await db.ApprovalWorkflows.AsNoTracking()
+                .Include(w => w.Steps).ThenInclude(s => s.Levels)
+                .FirstOrDefaultAsync(w => w.Id == p.ApprovalWorkflowId.Value, ct);
+            var allLevels = wf?.Steps.OrderBy(s => s.Order)
+                .SelectMany(s => s.Levels.OrderBy(l => l.Order))
+                .ToList() ?? new();
+            var currentLevel = allLevels.ElementAtOrDefault(p.CurrentApprovalLevelOrder.Value - 1);
+            if (currentLevel?.ApproverUserId != cu.UserId)
+                throw new ForbiddenException("Không phải người duyệt của cấp này.");
+        }
+
+        p.Status = WorkflowAppStatus.TuChoi;
+        p.CurrentApprovalLevelOrder = null;
+        p.UpdatedAt = clock.UtcNow;
+        p.UpdatedBy = cu.UserId;
+        await db.SaveChangesAsync(ct);
+    }
+}
+
+public record ReturnOtRequestCommand(Guid Id, string? Comment) : IRequest;
+
+public class ReturnOtRequestHandler(IApplicationDbContext db, ICurrentUser cu, IDateTime clock)
+    : IRequestHandler<ReturnOtRequestCommand>
+{
+    public async Task Handle(ReturnOtRequestCommand req, CancellationToken ct)
+    {
+        var p = await db.OtRequests.FirstOrDefaultAsync(x => x.Id == req.Id && !x.IsDeleted, ct);
+        if (p is null) throw new NotFoundException("OtRequest", req.Id);
+        if (p.Status != WorkflowAppStatus.DaGuiDuyet)
+            throw new ConflictException("Chỉ trả lại được khi đang trong workflow duyệt.");
+
+        var isAdmin = cu.Roles.Contains("Admin");
+        if (!isAdmin && p.CurrentApprovalLevelOrder.HasValue && p.ApprovalWorkflowId.HasValue)
+        {
+            var wf = await db.ApprovalWorkflows.AsNoTracking()
+                .Include(w => w.Steps).ThenInclude(s => s.Levels)
+                .FirstOrDefaultAsync(w => w.Id == p.ApprovalWorkflowId.Value, ct);
+            var allLevels = wf?.Steps.OrderBy(s => s.Order)
+                .SelectMany(s => s.Levels.OrderBy(l => l.Order))
+                .ToList() ?? new();
+            var currentLevel = allLevels.ElementAtOrDefault(p.CurrentApprovalLevelOrder.Value - 1);
+            if (currentLevel?.ApproverUserId != cu.UserId)
+                throw new ForbiddenException("Không phải người duyệt của cấp này.");
+        }
+
+        p.Status = WorkflowAppStatus.TraLai;
+        p.RejectedFromStatus = WorkflowAppStatus.DaGuiDuyet;
+        p.CurrentApprovalLevelOrder = null;
+        p.UpdatedAt = clock.UtcNow;
+        p.UpdatedBy = cu.UserId;
+        await db.SaveChangesAsync(ct);
+    }
+}
--- a/src/Backend/SolutionErp.Application/Office/TravelVehicleApprovalFeatures.cs
+++ b/src/Backend/SolutionErp.Application/Office/TravelVehicleApprovalFeatures.cs
@ -0,0 +1,773 @@
+using System.Data;
+using FluentValidation;
+using MediatR;
+using Microsoft.EntityFrameworkCore;
+using SolutionErp.Application.Common.Exceptions;
+using SolutionErp.Application.Common.Interfaces;
+using SolutionErp.Domain.ApprovalWorkflowsV2;
+using SolutionErp.Domain.Office;
+
+namespace SolutionErp.Application.Office;
+
+// Phase 11 P11-A Wave 2b (S41 2026-05-30) — Wire ApproveV2 CQRS cho TravelRequest + VehicleBooking.
+// Cookie-cutter mirror ProposalFeatures Region 2 (Mig 38). Schema Wave 1 (Mig 41) đã sẵn:
+//   TravelRequestLevelOpinions + VehicleBookingLevelOpinions + WorkflowAppCodeSequences
+//   parent +RejectedFromStatus + nav LevelOpinions.
+//
+// ApplicableType: TravelRequest=9 (Mig 41 mới) · VehicleBooking=7.
+// WorkflowAppStatus {Nhap=1, DaGuiDuyet=2, TraLai=3, TuChoi=4, DaDuyet=5}.
+//
+// Endpoint per module (qua {Travel,Vehicle}*Controller):
+//   GET    /{id}          — detail Include LevelOpinions + Workflow metadata
+//   PUT    /{id}          — update draft (Nhap or TraLai only)
+//   POST   /{id}/submit   — gen MaDonTu atomic + Status=DaGuiDuyet
+//   POST   /{id}/approve  — ApproveV2: UPSERT LevelOpinion + advance level/terminal
+//   POST   /{id}/reject   — Status=TuChoi terminal (no opinion sync)
+//   POST   /{id}/return   — Status=TraLai + RejectedFromStatus=DaGuiDuyet (no opinion sync)
+//
+// Note: GetList + Create giữ nguyên trong WorkflowAppsFeatures.cs (KHÔNG sửa file đó).
+
+// =========================================================================
+// REGION 1: TravelRequest — ApproveV2 wire
+// =========================================================================
+
+public record TravelRequestLevelOpinionDto(
+    Guid Id,
+    Guid ApprovalWorkflowLevelId,
+    int? StepOrder,
+    string? StepName,
+    int? LevelOrder,
+    Guid? ApproverUserId,
+    string? Comment,
+    DateTime SignedAt,
+    Guid SignedByUserId,
+    string SignedByFullName);
+
+public record TravelRequestDetailDto(
+    Guid Id,
+    string? MaDonTu,
+    Guid RequesterUserId,
+    string RequesterFullName,
+    string Destination,
+    DateTime StartDate,
+    DateTime EndDate,
+    int NumDays,
+    string Purpose,
+    decimal? EstimatedCost,
+    int Status,
+    Guid? ApprovalWorkflowId,
+    string? WorkflowCode,
+    string? WorkflowName,
+    int? CurrentApprovalLevelOrder,
+    int? RejectedFromStatus,
+    DateTime CreatedAt,
+    List<TravelRequestLevelOpinionDto> LevelOpinions);
+
+public record GetTravelRequestByIdQuery(Guid Id) : IRequest<TravelRequestDetailDto?>;
+
+public class GetTravelRequestByIdHandler(IApplicationDbContext db)
+    : IRequestHandler<GetTravelRequestByIdQuery, TravelRequestDetailDto?>
+{
+    public async Task<TravelRequestDetailDto?> Handle(GetTravelRequestByIdQuery req, CancellationToken ct)
+    {
+        var p = await db.TravelRequests.AsNoTracking()
+            .Include(x => x.LevelOpinions)
+            .FirstOrDefaultAsync(x => x.Id == req.Id && !x.IsDeleted, ct);
+        if (p is null) return null;
+
+        string? wfCode = null;
+        string? wfName = null;
+        if (p.ApprovalWorkflowId.HasValue)
+        {
+            var wf = await db.ApprovalWorkflows.AsNoTracking()
+                .Where(w => w.Id == p.ApprovalWorkflowId.Value)
+                .Select(w => new { w.Code, w.Name })
+                .FirstOrDefaultAsync(ct);
+            wfCode = wf?.Code;
+            wfName = wf?.Name;
+        }
+
+        var levelIds = p.LevelOpinions.Select(o => o.ApprovalWorkflowLevelId).Distinct().ToList();
+        var levels = await db.ApprovalWorkflowSteps.AsNoTracking()
+            .Where(s => s.Levels.Any(l => levelIds.Contains(l.Id)))
+            .Select(s => new
+            {
+                s.Id,
+                s.Order,
+                s.Name,
+                Levels = s.Levels.Where(l => levelIds.Contains(l.Id))
+                    .Select(l => new { l.Id, l.Order, l.ApproverUserId })
+                    .ToList(),
+            })
+            .ToListAsync(ct);
+
+        var levelLookup = levels.SelectMany(s => s.Levels.Select(l => new { Step = s, Level = l }))
+            .ToDictionary(x => x.Level.Id);
+
+        var opinions = p.LevelOpinions
+            .Select(o =>
+            {
+                levelLookup.TryGetValue(o.ApprovalWorkflowLevelId, out var lvl);
+                return new TravelRequestLevelOpinionDto(
+                    o.Id,
+                    o.ApprovalWorkflowLevelId,
+                    lvl?.Step.Order,
+                    lvl?.Step.Name,
+                    lvl?.Level.Order,
+                    lvl?.Level.ApproverUserId,
+                    o.Comment,
+                    o.SignedAt,
+                    o.SignedByUserId,
+                    o.SignedByFullName);
+            })
+            .OrderBy(o => o.StepOrder).ThenBy(o => o.LevelOrder)
+            .ToList();
+
+        return new TravelRequestDetailDto(
+            p.Id, p.MaDonTu, p.RequesterUserId, p.RequesterFullName,
+            p.Destination, p.StartDate, p.EndDate, p.NumDays, p.Purpose, p.EstimatedCost,
+            (int)p.Status, p.ApprovalWorkflowId, wfCode, wfName, p.CurrentApprovalLevelOrder,
+            p.RejectedFromStatus.HasValue ? (int)p.RejectedFromStatus.Value : (int?)null,
+            p.CreatedAt, opinions);
+    }
+}
+
+public record UpdateTravelRequestDraftCommand(
+    Guid Id,
+    string Destination,
+    DateTime StartDate,
+    DateTime EndDate,
+    int NumDays,
+    string Purpose,
+    decimal? EstimatedCost,
+    Guid? ApprovalWorkflowId) : IRequest;
+
+public class UpdateTravelRequestDraftValidator : AbstractValidator<UpdateTravelRequestDraftCommand>
+{
+    public UpdateTravelRequestDraftValidator()
+    {
+        RuleFor(x => x.Destination).NotEmpty().MaximumLength(300);
+        RuleFor(x => x.Purpose).NotEmpty().MaximumLength(1000);
+        RuleFor(x => x.NumDays).GreaterThan(0);
+        RuleFor(x => x.EstimatedCost).GreaterThanOrEqualTo(0).When(x => x.EstimatedCost.HasValue);
+    }
+}
+
+public class UpdateTravelRequestDraftHandler(IApplicationDbContext db, ICurrentUser currentUser, IDateTime clock)
+    : IRequestHandler<UpdateTravelRequestDraftCommand>
+{
+    public async Task Handle(UpdateTravelRequestDraftCommand req, CancellationToken ct)
+    {
+        var p = await db.TravelRequests.FirstOrDefaultAsync(x => x.Id == req.Id && !x.IsDeleted, ct);
+        if (p is null) throw new NotFoundException("TravelRequest", req.Id);
+
+        var isOwner = p.RequesterUserId == currentUser.UserId;
+        var isAdmin = currentUser.Roles.Contains("Admin");
+        if (!isOwner && !isAdmin)
+            throw new ForbiddenException("Chỉ người tạo hoặc Admin được sửa đơn công tác.");
+        if (p.Status != WorkflowAppStatus.Nhap && p.Status != WorkflowAppStatus.TraLai)
+            throw new ConflictException("Chỉ sửa được khi trạng thái Nháp hoặc Trả lại.");
+
+        if (req.ApprovalWorkflowId.HasValue && req.ApprovalWorkflowId != p.ApprovalWorkflowId)
+        {
+            var wfType = await db.ApprovalWorkflows.AsNoTracking()
+                .Where(w => w.Id == req.ApprovalWorkflowId.Value)
+                .Select(w => (int?)w.ApplicableType)
+                .FirstOrDefaultAsync(ct);
+            if (wfType is null)
+                throw new NotFoundException("ApprovalWorkflow", req.ApprovalWorkflowId.Value);
+            if (wfType.Value != (int)ApprovalWorkflowApplicableType.TravelRequest)
+                throw new ConflictException("Quy trình duyệt không thuộc loại Đơn công tác.");
+        }
+
+        p.Destination = req.Destination.Trim();
+        p.StartDate = req.StartDate;
+        p.EndDate = req.EndDate;
+        p.NumDays = req.NumDays;
+        p.Purpose = req.Purpose.Trim();
+        p.EstimatedCost = req.EstimatedCost;
+        p.ApprovalWorkflowId = req.ApprovalWorkflowId;
+        p.UpdatedAt = clock.UtcNow;
+        p.UpdatedBy = currentUser.UserId;
+        await db.SaveChangesAsync(ct);
+    }
+}
+
+public record SubmitTravelRequestCommand(Guid Id) : IRequest;
+
+public class SubmitTravelRequestHandler(IApplicationDbContext db, ICurrentUser currentUser, IDateTime clock)
+    : IRequestHandler<SubmitTravelRequestCommand>
+{
+    public async Task Handle(SubmitTravelRequestCommand req, CancellationToken ct)
+    {
+        var p = await db.TravelRequests.FirstOrDefaultAsync(x => x.Id == req.Id && !x.IsDeleted, ct);
+        if (p is null) throw new NotFoundException("TravelRequest", req.Id);
+
+        var isOwner = p.RequesterUserId == currentUser.UserId;
+        var isAdmin = currentUser.Roles.Contains("Admin");
+        if (!isOwner && !isAdmin)
+            throw new ForbiddenException("Chỉ người tạo hoặc Admin được gửi duyệt.");
+        if (p.Status != WorkflowAppStatus.Nhap && p.Status != WorkflowAppStatus.TraLai)
+            throw new ConflictException("Chỉ gửi duyệt được khi trạng thái Nháp hoặc Trả lại.");
+        if (!p.ApprovalWorkflowId.HasValue)
+            throw new ConflictException("Chưa chọn quy trình duyệt.");
+
+        var wfType = await db.ApprovalWorkflows.AsNoTracking()
+            .Where(w => w.Id == p.ApprovalWorkflowId.Value)
+            .Select(w => (int?)w.ApplicableType)
+            .FirstOrDefaultAsync(ct);
+        if (wfType is null)
+            throw new NotFoundException("ApprovalWorkflow", p.ApprovalWorkflowId.Value);
+        if (wfType.Value != (int)ApprovalWorkflowApplicableType.TravelRequest)
+            throw new ConflictException("Quy trình duyệt không thuộc loại Đơn công tác.");
+
+        if (string.IsNullOrEmpty(p.MaDonTu))
+        {
+            p.MaDonTu = await TravelVehicleCodeGen.GenerateMaDonTuAsync(
+                db, $"DT/CT/{clock.Now.Year}", clock, ct);
+        }
+
+        p.Status = WorkflowAppStatus.DaGuiDuyet;
+        p.CurrentApprovalLevelOrder = 1;
+        p.RejectedFromStatus = null;
+        p.UpdatedAt = clock.UtcNow;
+        p.UpdatedBy = currentUser.UserId;
+        await db.SaveChangesAsync(ct);
+    }
+}
+
+public record ApproveTravelRequestCommand(Guid Id, string? Comment) : IRequest;
+
+public class ApproveTravelRequestHandler(IApplicationDbContext db, ICurrentUser currentUser, IDateTime clock)
+    : IRequestHandler<ApproveTravelRequestCommand>
+{
+    public async Task Handle(ApproveTravelRequestCommand req, CancellationToken ct)
+    {
+        if (currentUser.UserId is null) throw new UnauthorizedException();
+
+        var p = await db.TravelRequests.FirstOrDefaultAsync(x => x.Id == req.Id && !x.IsDeleted, ct);
+        if (p is null) throw new NotFoundException("TravelRequest", req.Id);
+        if (p.Status != WorkflowAppStatus.DaGuiDuyet)
+            throw new ConflictException("Chỉ duyệt được khi trạng thái Đã gửi duyệt.");
+        if (!p.ApprovalWorkflowId.HasValue || !p.CurrentApprovalLevelOrder.HasValue)
+            throw new ConflictException("Quy trình duyệt chưa pin hoặc thiếu cấp hiện tại.");
+
+        var wf = await db.ApprovalWorkflows.AsNoTracking()
+            .Include(w => w.Steps).ThenInclude(s => s.Levels)
+            .FirstOrDefaultAsync(w => w.Id == p.ApprovalWorkflowId.Value, ct);
+        if (wf is null) throw new NotFoundException("ApprovalWorkflow", p.ApprovalWorkflowId.Value);
+
+        var allLevels = wf.Steps.OrderBy(s => s.Order)
+            .SelectMany(s => s.Levels.OrderBy(l => l.Order).Select(l => new { Step = s, Level = l }))
+            .ToList();
+        if (allLevels.Count == 0)
+            throw new ConflictException("Quy trình duyệt không có cấp duyệt.");
+
+        var currentSlot = allLevels.ElementAtOrDefault(p.CurrentApprovalLevelOrder.Value - 1);
+        if (currentSlot is null)
+            throw new ConflictException($"Cấp duyệt {p.CurrentApprovalLevelOrder.Value} không tồn tại trong quy trình.");
+
+        var isAdmin = currentUser.Roles.Contains("Admin");
+        if (!isAdmin && currentSlot.Level.ApproverUserId != currentUser.UserId.Value)
+            throw new ForbiddenException("Không phải người duyệt của cấp này.");
+
+        var existing = await db.TravelRequestLevelOpinions
+            .FirstOrDefaultAsync(o => o.TravelRequestId == p.Id && o.ApprovalWorkflowLevelId == currentSlot.Level.Id, ct);
+        var commentFinal = string.IsNullOrWhiteSpace(req.Comment)
+            ? "(duyệt — không ý kiến)"
+            : req.Comment.Trim();
+        if (existing is null)
+        {
+            db.TravelRequestLevelOpinions.Add(new TravelRequestLevelOpinion
+            {
+                TravelRequestId = p.Id,
+                ApprovalWorkflowLevelId = currentSlot.Level.Id,
+                Comment = commentFinal,
+                SignedAt = clock.UtcNow,
+                SignedByUserId = currentUser.UserId.Value,
+                SignedByFullName = currentUser.FullName ?? "(unknown)",
+                CreatedAt = clock.UtcNow,
+                CreatedBy = currentUser.UserId,
+            });
+        }
+        else
+        {
+            existing.Comment = commentFinal;
+            existing.SignedAt = clock.UtcNow;
+            existing.SignedByUserId = currentUser.UserId.Value;
+            existing.SignedByFullName = currentUser.FullName ?? "(unknown)";
+            existing.UpdatedAt = clock.UtcNow;
+            existing.UpdatedBy = currentUser.UserId;
+        }
+
+        if (p.CurrentApprovalLevelOrder.Value < allLevels.Count)
+        {
+            p.CurrentApprovalLevelOrder = p.CurrentApprovalLevelOrder.Value + 1;
+        }
+        else
+        {
+            p.Status = WorkflowAppStatus.DaDuyet;
+            p.CurrentApprovalLevelOrder = null;
+        }
+        p.UpdatedAt = clock.UtcNow;
+        p.UpdatedBy = currentUser.UserId;
+        await db.SaveChangesAsync(ct);
+    }
+}
+
+public record RejectTravelRequestCommand(Guid Id, string? Comment) : IRequest;
+
+public class RejectTravelRequestHandler(IApplicationDbContext db, ICurrentUser currentUser, IDateTime clock)
+    : IRequestHandler<RejectTravelRequestCommand>
+{
+    public async Task Handle(RejectTravelRequestCommand req, CancellationToken ct)
+    {
+        var p = await db.TravelRequests.FirstOrDefaultAsync(x => x.Id == req.Id && !x.IsDeleted, ct);
+        if (p is null) throw new NotFoundException("TravelRequest", req.Id);
+        if (p.Status != WorkflowAppStatus.DaGuiDuyet)
+            throw new ConflictException("Chỉ từ chối được khi đang trong workflow duyệt.");
+
+        var isAdmin = currentUser.Roles.Contains("Admin");
+        if (!isAdmin && p.CurrentApprovalLevelOrder.HasValue && p.ApprovalWorkflowId.HasValue)
+        {
+            var wf = await db.ApprovalWorkflows.AsNoTracking()
+                .Include(w => w.Steps).ThenInclude(s => s.Levels)
+                .FirstOrDefaultAsync(w => w.Id == p.ApprovalWorkflowId.Value, ct);
+            var allLevels = wf?.Steps.OrderBy(s => s.Order)
+                .SelectMany(s => s.Levels.OrderBy(l => l.Order))
+                .ToList() ?? new();
+            var currentLevel = allLevels.ElementAtOrDefault(p.CurrentApprovalLevelOrder.Value - 1);
+            if (currentLevel?.ApproverUserId != currentUser.UserId)
+                throw new ForbiddenException("Không phải người duyệt của cấp này.");
+        }
+
+        p.Status = WorkflowAppStatus.TuChoi;
+        p.CurrentApprovalLevelOrder = null;
+        p.UpdatedAt = clock.UtcNow;
+        p.UpdatedBy = currentUser.UserId;
+        await db.SaveChangesAsync(ct);
+    }
+}
+
+public record ReturnTravelRequestCommand(Guid Id, string? Comment) : IRequest;
+
+public class ReturnTravelRequestHandler(IApplicationDbContext db, ICurrentUser currentUser, IDateTime clock)
+    : IRequestHandler<ReturnTravelRequestCommand>
+{
+    public async Task Handle(ReturnTravelRequestCommand req, CancellationToken ct)
+    {
+        var p = await db.TravelRequests.FirstOrDefaultAsync(x => x.Id == req.Id && !x.IsDeleted, ct);
+        if (p is null) throw new NotFoundException("TravelRequest", req.Id);
+        if (p.Status != WorkflowAppStatus.DaGuiDuyet)
+            throw new ConflictException("Chỉ trả lại được khi đang trong workflow duyệt.");
+
+        var isAdmin = currentUser.Roles.Contains("Admin");
+        if (!isAdmin && p.CurrentApprovalLevelOrder.HasValue && p.ApprovalWorkflowId.HasValue)
+        {
+            var wf = await db.ApprovalWorkflows.AsNoTracking()
+                .Include(w => w.Steps).ThenInclude(s => s.Levels)
+                .FirstOrDefaultAsync(w => w.Id == p.ApprovalWorkflowId.Value, ct);
+            var allLevels = wf?.Steps.OrderBy(s => s.Order)
+                .SelectMany(s => s.Levels.OrderBy(l => l.Order))
+                .ToList() ?? new();
+            var currentLevel = allLevels.ElementAtOrDefault(p.CurrentApprovalLevelOrder.Value - 1);
+            if (currentLevel?.ApproverUserId != currentUser.UserId)
+                throw new ForbiddenException("Không phải người duyệt của cấp này.");
+        }
+
+        p.Status = WorkflowAppStatus.TraLai;
+        p.RejectedFromStatus = WorkflowAppStatus.DaGuiDuyet;
+        p.CurrentApprovalLevelOrder = null;
+        p.UpdatedAt = clock.UtcNow;
+        p.UpdatedBy = currentUser.UserId;
+        await db.SaveChangesAsync(ct);
+    }
+}
+
+// =========================================================================
+// REGION 2: VehicleBooking — ApproveV2 wire
+// =========================================================================
+
+public record VehicleBookingLevelOpinionDto(
+    Guid Id,
+    Guid ApprovalWorkflowLevelId,
+    int? StepOrder,
+    string? StepName,
+    int? LevelOrder,
+    Guid? ApproverUserId,
+    string? Comment,
+    DateTime SignedAt,
+    Guid SignedByUserId,
+    string SignedByFullName);
+
+public record VehicleBookingDetailDto(
+    Guid Id,
+    string? MaDonTu,
+    Guid RequesterUserId,
+    string RequesterFullName,
+    string VehicleLicense,
+    string? VehicleName,
+    DateTime StartAt,
+    DateTime EndAt,
+    string Destination,
+    string Purpose,
+    string? DriverName,
+    int Status,
+    Guid? ApprovalWorkflowId,
+    string? WorkflowCode,
+    string? WorkflowName,
+    int? CurrentApprovalLevelOrder,
+    int? RejectedFromStatus,
+    DateTime CreatedAt,
+    List<VehicleBookingLevelOpinionDto> LevelOpinions);
+
+public record GetVehicleBookingByIdQuery(Guid Id) : IRequest<VehicleBookingDetailDto?>;
+
+public class GetVehicleBookingByIdHandler(IApplicationDbContext db)
+    : IRequestHandler<GetVehicleBookingByIdQuery, VehicleBookingDetailDto?>
+{
+    public async Task<VehicleBookingDetailDto?> Handle(GetVehicleBookingByIdQuery req, CancellationToken ct)
+    {
+        var p = await db.VehicleBookings.AsNoTracking()
+            .Include(x => x.LevelOpinions)
+            .FirstOrDefaultAsync(x => x.Id == req.Id && !x.IsDeleted, ct);
+        if (p is null) return null;
+
+        string? wfCode = null;
+        string? wfName = null;
+        if (p.ApprovalWorkflowId.HasValue)
+        {
+            var wf = await db.ApprovalWorkflows.AsNoTracking()
+                .Where(w => w.Id == p.ApprovalWorkflowId.Value)
+                .Select(w => new { w.Code, w.Name })
+                .FirstOrDefaultAsync(ct);
+            wfCode = wf?.Code;
+            wfName = wf?.Name;
+        }
+
+        var levelIds = p.LevelOpinions.Select(o => o.ApprovalWorkflowLevelId).Distinct().ToList();
+        var levels = await db.ApprovalWorkflowSteps.AsNoTracking()
+            .Where(s => s.Levels.Any(l => levelIds.Contains(l.Id)))
+            .Select(s => new
+            {
+                s.Id,
+                s.Order,
+                s.Name,
+                Levels = s.Levels.Where(l => levelIds.Contains(l.Id))
+                    .Select(l => new { l.Id, l.Order, l.ApproverUserId })
+                    .ToList(),
+            })
+            .ToListAsync(ct);
+
+        var levelLookup = levels.SelectMany(s => s.Levels.Select(l => new { Step = s, Level = l }))
+            .ToDictionary(x => x.Level.Id);
+
+        var opinions = p.LevelOpinions
+            .Select(o =>
+            {
+                levelLookup.TryGetValue(o.ApprovalWorkflowLevelId, out var lvl);
+                return new VehicleBookingLevelOpinionDto(
+                    o.Id,
+                    o.ApprovalWorkflowLevelId,
+                    lvl?.Step.Order,
+                    lvl?.Step.Name,
+                    lvl?.Level.Order,
+                    lvl?.Level.ApproverUserId,
+                    o.Comment,
+                    o.SignedAt,
+                    o.SignedByUserId,
+                    o.SignedByFullName);
+            })
+            .OrderBy(o => o.StepOrder).ThenBy(o => o.LevelOrder)
+            .ToList();
+
+        return new VehicleBookingDetailDto(
+            p.Id, p.MaDonTu, p.RequesterUserId, p.RequesterFullName,
+            p.VehicleLicense, p.VehicleName, p.StartAt, p.EndAt, p.Destination, p.Purpose, p.DriverName,
+            (int)p.Status, p.ApprovalWorkflowId, wfCode, wfName, p.CurrentApprovalLevelOrder,
+            p.RejectedFromStatus.HasValue ? (int)p.RejectedFromStatus.Value : (int?)null,
+            p.CreatedAt, opinions);
+    }
+}
+
+public record UpdateVehicleBookingDraftCommand(
+    Guid Id,
+    string VehicleLicense,
+    string? VehicleName,
+    DateTime StartAt,
+    DateTime EndAt,
+    string Destination,
+    string Purpose,
+    string? DriverName,
+    Guid? ApprovalWorkflowId) : IRequest;
+
+public class UpdateVehicleBookingDraftValidator : AbstractValidator<UpdateVehicleBookingDraftCommand>
+{
+    public UpdateVehicleBookingDraftValidator()
+    {
+        RuleFor(x => x.VehicleLicense).NotEmpty().MaximumLength(20);
+        RuleFor(x => x.Destination).NotEmpty().MaximumLength(300);
+        RuleFor(x => x.Purpose).NotEmpty().MaximumLength(1000);
+        RuleFor(x => x.EndAt).GreaterThan(x => x.StartAt);
+    }
+}
+
+public class UpdateVehicleBookingDraftHandler(IApplicationDbContext db, ICurrentUser currentUser, IDateTime clock)
+    : IRequestHandler<UpdateVehicleBookingDraftCommand>
+{
+    public async Task Handle(UpdateVehicleBookingDraftCommand req, CancellationToken ct)
+    {
+        var p = await db.VehicleBookings.FirstOrDefaultAsync(x => x.Id == req.Id && !x.IsDeleted, ct);
+        if (p is null) throw new NotFoundException("VehicleBooking", req.Id);
+
+        var isOwner = p.RequesterUserId == currentUser.UserId;
+        var isAdmin = currentUser.Roles.Contains("Admin");
+        if (!isOwner && !isAdmin)
+            throw new ForbiddenException("Chỉ người tạo hoặc Admin được sửa đơn đặt xe.");
+        if (p.Status != WorkflowAppStatus.Nhap && p.Status != WorkflowAppStatus.TraLai)
+            throw new ConflictException("Chỉ sửa được khi trạng thái Nháp hoặc Trả lại.");
+
+        if (req.ApprovalWorkflowId.HasValue && req.ApprovalWorkflowId != p.ApprovalWorkflowId)
+        {
+            var wfType = await db.ApprovalWorkflows.AsNoTracking()
+                .Where(w => w.Id == req.ApprovalWorkflowId.Value)
+                .Select(w => (int?)w.ApplicableType)
+                .FirstOrDefaultAsync(ct);
+            if (wfType is null)
+                throw new NotFoundException("ApprovalWorkflow", req.ApprovalWorkflowId.Value);
+            if (wfType.Value != (int)ApprovalWorkflowApplicableType.VehicleBooking)
+                throw new ConflictException("Quy trình duyệt không thuộc loại Đặt xe.");
+        }
+
+        p.VehicleLicense = req.VehicleLicense.Trim();
+        p.VehicleName = req.VehicleName?.Trim();
+        p.StartAt = req.StartAt;
+        p.EndAt = req.EndAt;
+        p.Destination = req.Destination.Trim();
+        p.Purpose = req.Purpose.Trim();
+        p.DriverName = req.DriverName?.Trim();
+        p.ApprovalWorkflowId = req.ApprovalWorkflowId;
+        p.UpdatedAt = clock.UtcNow;
+        p.UpdatedBy = currentUser.UserId;
+        await db.SaveChangesAsync(ct);
+    }
+}
+
+public record SubmitVehicleBookingCommand(Guid Id) : IRequest;
+
+public class SubmitVehicleBookingHandler(IApplicationDbContext db, ICurrentUser currentUser, IDateTime clock)
+    : IRequestHandler<SubmitVehicleBookingCommand>
+{
+    public async Task Handle(SubmitVehicleBookingCommand req, CancellationToken ct)
+    {
+        var p = await db.VehicleBookings.FirstOrDefaultAsync(x => x.Id == req.Id && !x.IsDeleted, ct);
+        if (p is null) throw new NotFoundException("VehicleBooking", req.Id);
+
+        var isOwner = p.RequesterUserId == currentUser.UserId;
+        var isAdmin = currentUser.Roles.Contains("Admin");
+        if (!isOwner && !isAdmin)
+            throw new ForbiddenException("Chỉ người tạo hoặc Admin được gửi duyệt.");
+        if (p.Status != WorkflowAppStatus.Nhap && p.Status != WorkflowAppStatus.TraLai)
+            throw new ConflictException("Chỉ gửi duyệt được khi trạng thái Nháp hoặc Trả lại.");
+        if (!p.ApprovalWorkflowId.HasValue)
+            throw new ConflictException("Chưa chọn quy trình duyệt.");
+
+        var wfType = await db.ApprovalWorkflows.AsNoTracking()
+            .Where(w => w.Id == p.ApprovalWorkflowId.Value)
+            .Select(w => (int?)w.ApplicableType)
+            .FirstOrDefaultAsync(ct);
+        if (wfType is null)
+            throw new NotFoundException("ApprovalWorkflow", p.ApprovalWorkflowId.Value);
+        if (wfType.Value != (int)ApprovalWorkflowApplicableType.VehicleBooking)
+            throw new ConflictException("Quy trình duyệt không thuộc loại Đặt xe.");
+
+        if (string.IsNullOrEmpty(p.MaDonTu))
+        {
+            p.MaDonTu = await TravelVehicleCodeGen.GenerateMaDonTuAsync(
+                db, $"DX/XE/{clock.Now.Year}", clock, ct);
+        }
+
+        p.Status = WorkflowAppStatus.DaGuiDuyet;
+        p.CurrentApprovalLevelOrder = 1;
+        p.RejectedFromStatus = null;
+        p.UpdatedAt = clock.UtcNow;
+        p.UpdatedBy = currentUser.UserId;
+        await db.SaveChangesAsync(ct);
+    }
+}
+
+public record ApproveVehicleBookingCommand(Guid Id, string? Comment) : IRequest;
+
+public class ApproveVehicleBookingHandler(IApplicationDbContext db, ICurrentUser currentUser, IDateTime clock)
+    : IRequestHandler<ApproveVehicleBookingCommand>
+{
+    public async Task Handle(ApproveVehicleBookingCommand req, CancellationToken ct)
+    {
+        if (currentUser.UserId is null) throw new UnauthorizedException();
+
+        var p = await db.VehicleBookings.FirstOrDefaultAsync(x => x.Id == req.Id && !x.IsDeleted, ct);
+        if (p is null) throw new NotFoundException("VehicleBooking", req.Id);
+        if (p.Status != WorkflowAppStatus.DaGuiDuyet)
+            throw new ConflictException("Chỉ duyệt được khi trạng thái Đã gửi duyệt.");
+        if (!p.ApprovalWorkflowId.HasValue || !p.CurrentApprovalLevelOrder.HasValue)
+            throw new ConflictException("Quy trình duyệt chưa pin hoặc thiếu cấp hiện tại.");
+
+        var wf = await db.ApprovalWorkflows.AsNoTracking()
+            .Include(w => w.Steps).ThenInclude(s => s.Levels)
+            .FirstOrDefaultAsync(w => w.Id == p.ApprovalWorkflowId.Value, ct);
+        if (wf is null) throw new NotFoundException("ApprovalWorkflow", p.ApprovalWorkflowId.Value);
+
+        var allLevels = wf.Steps.OrderBy(s => s.Order)
+            .SelectMany(s => s.Levels.OrderBy(l => l.Order).Select(l => new { Step = s, Level = l }))
+            .ToList();
+        if (allLevels.Count == 0)
+            throw new ConflictException("Quy trình duyệt không có cấp duyệt.");
+
+        var currentSlot = allLevels.ElementAtOrDefault(p.CurrentApprovalLevelOrder.Value - 1);
+        if (currentSlot is null)
+            throw new ConflictException($"Cấp duyệt {p.CurrentApprovalLevelOrder.Value} không tồn tại trong quy trình.");
+
+        var isAdmin = currentUser.Roles.Contains("Admin");
+        if (!isAdmin && currentSlot.Level.ApproverUserId != currentUser.UserId.Value)
+            throw new ForbiddenException("Không phải người duyệt của cấp này.");
+
+        var existing = await db.VehicleBookingLevelOpinions
+            .FirstOrDefaultAsync(o => o.VehicleBookingId == p.Id && o.ApprovalWorkflowLevelId == currentSlot.Level.Id, ct);
+        var commentFinal = string.IsNullOrWhiteSpace(req.Comment)
+            ? "(duyệt — không ý kiến)"
+            : req.Comment.Trim();
+        if (existing is null)
+        {
+            db.VehicleBookingLevelOpinions.Add(new VehicleBookingLevelOpinion
+            {
+                VehicleBookingId = p.Id,
+                ApprovalWorkflowLevelId = currentSlot.Level.Id,
+                Comment = commentFinal,
+                SignedAt = clock.UtcNow,
+                SignedByUserId = currentUser.UserId.Value,
+                SignedByFullName = currentUser.FullName ?? "(unknown)",
+                CreatedAt = clock.UtcNow,
+                CreatedBy = currentUser.UserId,
+            });
+        }
+        else
+        {
+            existing.Comment = commentFinal;
+            existing.SignedAt = clock.UtcNow;
+            existing.SignedByUserId = currentUser.UserId.Value;
+            existing.SignedByFullName = currentUser.FullName ?? "(unknown)";
+            existing.UpdatedAt = clock.UtcNow;
+            existing.UpdatedBy = currentUser.UserId;
+        }
+
+        if (p.CurrentApprovalLevelOrder.Value < allLevels.Count)
+        {
+            p.CurrentApprovalLevelOrder = p.CurrentApprovalLevelOrder.Value + 1;
+        }
+        else
+        {
+            p.Status = WorkflowAppStatus.DaDuyet;
+            p.CurrentApprovalLevelOrder = null;
+        }
+        p.UpdatedAt = clock.UtcNow;
+        p.UpdatedBy = currentUser.UserId;
+        await db.SaveChangesAsync(ct);
+    }
+}
+
+public record RejectVehicleBookingCommand(Guid Id, string? Comment) : IRequest;
+
+public class RejectVehicleBookingHandler(IApplicationDbContext db, ICurrentUser currentUser, IDateTime clock)
+    : IRequestHandler<RejectVehicleBookingCommand>
+{
+    public async Task Handle(RejectVehicleBookingCommand req, CancellationToken ct)
+    {
+        var p = await db.VehicleBookings.FirstOrDefaultAsync(x => x.Id == req.Id && !x.IsDeleted, ct);
+        if (p is null) throw new NotFoundException("VehicleBooking", req.Id);
+        if (p.Status != WorkflowAppStatus.DaGuiDuyet)
+            throw new ConflictException("Chỉ từ chối được khi đang trong workflow duyệt.");
+
+        var isAdmin = currentUser.Roles.Contains("Admin");
+        if (!isAdmin && p.CurrentApprovalLevelOrder.HasValue && p.ApprovalWorkflowId.HasValue)
+        {
+            var wf = await db.ApprovalWorkflows.AsNoTracking()
+                .Include(w => w.Steps).ThenInclude(s => s.Levels)
+                .FirstOrDefaultAsync(w => w.Id == p.ApprovalWorkflowId.Value, ct);
+            var allLevels = wf?.Steps.OrderBy(s => s.Order)
+                .SelectMany(s => s.Levels.OrderBy(l => l.Order))
+                .ToList() ?? new();
+            var currentLevel = allLevels.ElementAtOrDefault(p.CurrentApprovalLevelOrder.Value - 1);
+            if (currentLevel?.ApproverUserId != currentUser.UserId)
+                throw new ForbiddenException("Không phải người duyệt của cấp này.");
+        }
+
+        p.Status = WorkflowAppStatus.TuChoi;
+        p.CurrentApprovalLevelOrder = null;
+        p.UpdatedAt = clock.UtcNow;
+        p.UpdatedBy = currentUser.UserId;
+        await db.SaveChangesAsync(ct);
+    }
+}
+
+public record ReturnVehicleBookingCommand(Guid Id, string? Comment) : IRequest;
+
+public class ReturnVehicleBookingHandler(IApplicationDbContext db, ICurrentUser currentUser, IDateTime clock)
+    : IRequestHandler<ReturnVehicleBookingCommand>
+{
+    public async Task Handle(ReturnVehicleBookingCommand req, CancellationToken ct)
+    {
+        var p = await db.VehicleBookings.FirstOrDefaultAsync(x => x.Id == req.Id && !x.IsDeleted, ct);
+        if (p is null) throw new NotFoundException("VehicleBooking", req.Id);
+        if (p.Status != WorkflowAppStatus.DaGuiDuyet)
+            throw new ConflictException("Chỉ trả lại được khi đang trong workflow duyệt.");
+
+        var isAdmin = currentUser.Roles.Contains("Admin");
+        if (!isAdmin && p.CurrentApprovalLevelOrder.HasValue && p.ApprovalWorkflowId.HasValue)
+        {
+            var wf = await db.ApprovalWorkflows.AsNoTracking()
+                .Include(w => w.Steps).ThenInclude(s => s.Levels)
+                .FirstOrDefaultAsync(w => w.Id == p.ApprovalWorkflowId.Value, ct);
+            var allLevels = wf?.Steps.OrderBy(s => s.Order)
+                .SelectMany(s => s.Levels.OrderBy(l => l.Order))
+                .ToList() ?? new();
+            var currentLevel = allLevels.ElementAtOrDefault(p.CurrentApprovalLevelOrder.Value - 1);
+            if (currentLevel?.ApproverUserId != currentUser.UserId)
+                throw new ForbiddenException("Không phải người duyệt của cấp này.");
+        }
+
+        p.Status = WorkflowAppStatus.TraLai;
+        p.RejectedFromStatus = WorkflowAppStatus.DaGuiDuyet;
+        p.CurrentApprovalLevelOrder = null;
+        p.UpdatedAt = clock.UtcNow;
+        p.UpdatedBy = currentUser.UserId;
+        await db.SaveChangesAsync(ct);
+    }
+}
+
+// =========================================================================
+// Shared CodeGen helper — Prefix-keyed WorkflowAppCodeSequences (SERIALIZABLE tx).
+// Mirror SubmitProposalHandler.GenerateMaDeXuatAsync. Format: {prefix}/{seq:D3}.
+//   Travel  prefix = "DT/CT/{year}"
+//   Vehicle prefix = "DX/XE/{year}"
+// =========================================================================
+
+internal static class TravelVehicleCodeGen
+{
+    internal static async Task<string> GenerateMaDonTuAsync(
+        IApplicationDbContext db, string prefix, IDateTime clock, CancellationToken ct)
+    {
+        var dbContext = (DbContext)db;
+        await using var tx = await dbContext.Database.BeginTransactionAsync(IsolationLevel.Serializable, ct);
+        var seq = await db.WorkflowAppCodeSequences.FirstOrDefaultAsync(s => s.Prefix == prefix, ct);
+        if (seq is null)
+        {
+            seq = new WorkflowAppCodeSequence { Prefix = prefix, LastSeq = 0, UpdatedAt = clock.UtcNow };
+            db.WorkflowAppCodeSequences.Add(seq);
+        }
+        seq.LastSeq++;
+        seq.UpdatedAt = clock.UtcNow;
+        await db.SaveChangesAsync(ct);
+        await tx.CommitAsync(ct);
+        return $"{prefix}/{seq.LastSeq:D3}";
+    }
+}
--- a/src/Backend/SolutionErp.Domain/ApprovalWorkflowsV2/ApprovalWorkflow.cs
+++ b/src/Backend/SolutionErp.Domain/ApprovalWorkflowsV2/ApprovalWorkflow.cs
@ -55,6 +55,7 @@ public enum ApprovalWorkflowApplicableType
    OtRequest = 6,                  // G-O4 — Đơn OT
    VehicleBooking = 7,             // G-O5 — Đặt xe công
    ItTicket = 8,                   // G-O6 — Ticket CNTT
+    TravelRequest = 9,              // G-O4 — Đơn công tác (Travel) — Phase 11 P11-A
 }

 // Bước = Phòng. 1 quy trình có nhiều bước theo Order.
--- a/src/Backend/SolutionErp.Domain/Office/LeaveRequest.cs
+++ b/src/Backend/SolutionErp.Domain/Office/LeaveRequest.cs
@ -19,4 +19,7 @@ public class LeaveRequest : AuditableEntity
    public WorkflowAppStatus Status { get; set; } = WorkflowAppStatus.Nhap;
    public Guid? ApprovalWorkflowId { get; set; }         // pin ApplicableType=5
    public int? CurrentApprovalLevelOrder { get; set; }
+
+    public WorkflowAppStatus? RejectedFromStatus { get; set; }   // smart return tracking (mirror Proposal)
+    public List<LeaveRequestLevelOpinion> LevelOpinions { get; set; } = new();
 }
--- a/src/Backend/SolutionErp.Domain/Office/LeaveRequestLevelOpinion.cs
+++ b/src/Backend/SolutionErp.Domain/Office/LeaveRequestLevelOpinion.cs
@ -0,0 +1,28 @@
+using SolutionErp.Domain.ApprovalWorkflowsV2;
+using SolutionErp.Domain.Common;
+
+namespace SolutionErp.Domain.Office;
+
+// Phase 11 P11-A (Mig 41) — Ý kiến cấp duyệt V2 dynamic cho LeaveRequest.
+// Cookie-cutter mirror ProposalLevelOpinion (Mig 38).
+//
+// Mỗi row = 1 (LeaveRequest × ApprovalWorkflowLevel). Service ApproveV2Async sau
+// khi approve thành công Cấp hiện tại sẽ UPSERT row này (latest-write-wins).
+// Reject (TraLai/TuChoi) KHÔNG sync.
+//
+// UNIQUE composite (LeaveRequestId, ApprovalWorkflowLevelId) — 1 row / level / đơn.
+// FK Cascade LeaveRequest (wipe khi xoá) + Restrict Level (admin xoá Level chặn).
+// SignedByUserId track actor thật (có thể Admin override) + denorm FullName.
+public class LeaveRequestLevelOpinion : AuditableEntity
+{
+    public Guid LeaveRequestId { get; set; }
+    public Guid ApprovalWorkflowLevelId { get; set; }
+
+    public string? Comment { get; set; }                 // max 2000 hoặc placeholder
+    public DateTime SignedAt { get; set; }
+    public Guid SignedByUserId { get; set; }             // người ký thực sự (có thể Admin thay)
+    public string SignedByFullName { get; set; } = string.Empty;  // snapshot denorm
+
+    public LeaveRequest? LeaveRequest { get; set; }
+    public ApprovalWorkflowLevel? Level { get; set; }
+}
--- a/src/Backend/SolutionErp.Domain/Office/OtRequest.cs
+++ b/src/Backend/SolutionErp.Domain/Office/OtRequest.cs
@ -19,4 +19,7 @@ public class OtRequest : AuditableEntity
    public WorkflowAppStatus Status { get; set; } = WorkflowAppStatus.Nhap;
    public Guid? ApprovalWorkflowId { get; set; }
    public int? CurrentApprovalLevelOrder { get; set; }
+
+    public WorkflowAppStatus? RejectedFromStatus { get; set; }   // smart return tracking (mirror Proposal)
+    public List<OtRequestLevelOpinion> LevelOpinions { get; set; } = new();
 }
--- a/src/Backend/SolutionErp.Domain/Office/OtRequestLevelOpinion.cs
+++ b/src/Backend/SolutionErp.Domain/Office/OtRequestLevelOpinion.cs
@ -0,0 +1,28 @@
+using SolutionErp.Domain.ApprovalWorkflowsV2;
+using SolutionErp.Domain.Common;
+
+namespace SolutionErp.Domain.Office;
+
+// Phase 11 P11-A (Mig 41) — Ý kiến cấp duyệt V2 dynamic cho OtRequest.
+// Cookie-cutter mirror ProposalLevelOpinion (Mig 38).
+//
+// Mỗi row = 1 (OtRequest × ApprovalWorkflowLevel). Service ApproveV2Async sau
+// khi approve thành công Cấp hiện tại sẽ UPSERT row này (latest-write-wins).
+// Reject (TraLai/TuChoi) KHÔNG sync.
+//
+// UNIQUE composite (OtRequestId, ApprovalWorkflowLevelId) — 1 row / level / đơn.
+// FK Cascade OtRequest (wipe khi xoá) + Restrict Level (admin xoá Level chặn).
+// SignedByUserId track actor thật (có thể Admin override) + denorm FullName.
+public class OtRequestLevelOpinion : AuditableEntity
+{
+    public Guid OtRequestId { get; set; }
+    public Guid ApprovalWorkflowLevelId { get; set; }
+
+    public string? Comment { get; set; }                 // max 2000 hoặc placeholder
+    public DateTime SignedAt { get; set; }
+    public Guid SignedByUserId { get; set; }             // người ký thực sự (có thể Admin thay)
+    public string SignedByFullName { get; set; } = string.Empty;  // snapshot denorm
+
+    public OtRequest? OtRequest { get; set; }
+    public ApprovalWorkflowLevel? Level { get; set; }
+}
--- a/src/Backend/SolutionErp.Domain/Office/TravelRequest.cs
+++ b/src/Backend/SolutionErp.Domain/Office/TravelRequest.cs
@ -18,4 +18,7 @@ public class TravelRequest : AuditableEntity
    public WorkflowAppStatus Status { get; set; } = WorkflowAppStatus.Nhap;
    public Guid? ApprovalWorkflowId { get; set; }
    public int? CurrentApprovalLevelOrder { get; set; }
+
+    public WorkflowAppStatus? RejectedFromStatus { get; set; }   // smart return tracking (mirror Proposal)
+    public List<TravelRequestLevelOpinion> LevelOpinions { get; set; } = new();
 }
--- a/src/Backend/SolutionErp.Domain/Office/TravelRequestLevelOpinion.cs
+++ b/src/Backend/SolutionErp.Domain/Office/TravelRequestLevelOpinion.cs
@ -0,0 +1,28 @@
+using SolutionErp.Domain.ApprovalWorkflowsV2;
+using SolutionErp.Domain.Common;
+
+namespace SolutionErp.Domain.Office;
+
+// Phase 11 P11-A (Mig 41) — Ý kiến cấp duyệt V2 dynamic cho TravelRequest.
+// Cookie-cutter mirror ProposalLevelOpinion (Mig 38).
+//
+// Mỗi row = 1 (TravelRequest × ApprovalWorkflowLevel). Service ApproveV2Async sau
+// khi approve thành công Cấp hiện tại sẽ UPSERT row này (latest-write-wins).
+// Reject (TraLai/TuChoi) KHÔNG sync.
+//
+// UNIQUE composite (TravelRequestId, ApprovalWorkflowLevelId) — 1 row / level / đơn.
+// FK Cascade TravelRequest (wipe khi xoá) + Restrict Level (admin xoá Level chặn).
+// SignedByUserId track actor thật (có thể Admin override) + denorm FullName.
+public class TravelRequestLevelOpinion : AuditableEntity
+{
+    public Guid TravelRequestId { get; set; }
+    public Guid ApprovalWorkflowLevelId { get; set; }
+
+    public string? Comment { get; set; }                 // max 2000 hoặc placeholder
+    public DateTime SignedAt { get; set; }
+    public Guid SignedByUserId { get; set; }             // người ký thực sự (có thể Admin thay)
+    public string SignedByFullName { get; set; } = string.Empty;  // snapshot denorm
+
+    public TravelRequest? TravelRequest { get; set; }
+    public ApprovalWorkflowLevel? Level { get; set; }
+}
--- a/src/Backend/SolutionErp.Domain/Office/VehicleBooking.cs
+++ b/src/Backend/SolutionErp.Domain/Office/VehicleBooking.cs
@ -20,4 +20,7 @@ public class VehicleBooking : AuditableEntity
    public WorkflowAppStatus Status { get; set; } = WorkflowAppStatus.Nhap;
    public Guid? ApprovalWorkflowId { get; set; }
    public int? CurrentApprovalLevelOrder { get; set; }
+
+    public WorkflowAppStatus? RejectedFromStatus { get; set; }   // smart return tracking (mirror Proposal)
+    public List<VehicleBookingLevelOpinion> LevelOpinions { get; set; } = new();
 }
--- a/src/Backend/SolutionErp.Domain/Office/VehicleBookingLevelOpinion.cs
+++ b/src/Backend/SolutionErp.Domain/Office/VehicleBookingLevelOpinion.cs
@ -0,0 +1,28 @@
+using SolutionErp.Domain.ApprovalWorkflowsV2;
+using SolutionErp.Domain.Common;
+
+namespace SolutionErp.Domain.Office;
+
+// Phase 11 P11-A (Mig 41) — Ý kiến cấp duyệt V2 dynamic cho VehicleBooking.
+// Cookie-cutter mirror ProposalLevelOpinion (Mig 38).
+//
+// Mỗi row = 1 (VehicleBooking × ApprovalWorkflowLevel). Service ApproveV2Async sau
+// khi approve thành công Cấp hiện tại sẽ UPSERT row này (latest-write-wins).
+// Reject (TraLai/TuChoi) KHÔNG sync.
+//
+// UNIQUE composite (VehicleBookingId, ApprovalWorkflowLevelId) — 1 row / level / đơn.
+// FK Cascade VehicleBooking (wipe khi xoá) + Restrict Level (admin xoá Level chặn).
+// SignedByUserId track actor thật (có thể Admin override) + denorm FullName.
+public class VehicleBookingLevelOpinion : AuditableEntity
+{
+    public Guid VehicleBookingId { get; set; }
+    public Guid ApprovalWorkflowLevelId { get; set; }
+
+    public string? Comment { get; set; }                 // max 2000 hoặc placeholder
+    public DateTime SignedAt { get; set; }
+    public Guid SignedByUserId { get; set; }             // người ký thực sự (có thể Admin thay)
+    public string SignedByFullName { get; set; } = string.Empty;  // snapshot denorm
+
+    public VehicleBooking? VehicleBooking { get; set; }
+    public ApprovalWorkflowLevel? Level { get; set; }
+}
--- a/src/Backend/SolutionErp.Domain/Office/WorkflowAppCodeSequence.cs
+++ b/src/Backend/SolutionErp.Domain/Office/WorkflowAppCodeSequence.cs
@ -0,0 +1,19 @@
+namespace SolutionErp.Domain.Office;
+
+// Phase 11 P11-A (Mig 41) — Sequence generator dùng chung cho mã đơn từ (MaDonTu)
+// của 4 WorkflowApps module (Leave / OT / Travel / VehicleBooking).
+// Mirror ProposalCodeSequence pattern (Prefix string PK + LastSeq atomic).
+//
+// Prefix-keyed per module per năm, vd:
+//   "DT/LR/2026" (Leave)  → "DT/LR/2026/001" → "DT/LR/2026/002" → ...
+//   "DT/OT/2026" (OT)
+//   "DT/CT/2026" (Travel — Công tác)
+//   "DX/XE/2026" (VehicleBooking — Đặt xe)
+// LastSeq reset đầu năm tự nhiên (key Prefix mới). Update atomic qua
+// SERIALIZABLE transaction trong CodeGen service.
+public class WorkflowAppCodeSequence
+{
+    public string Prefix { get; set; } = string.Empty;     // PK — "DT/LR/2026"
+    public int LastSeq { get; set; }
+    public DateTime UpdatedAt { get; set; }
+}
--- a/src/Backend/SolutionErp.Infrastructure/Persistence/ApplicationDbContext.cs
+++ b/src/Backend/SolutionErp.Infrastructure/Persistence/ApplicationDbContext.cs
@ -115,6 +115,13 @@ public class ApplicationDbContext
    public DbSet<VehicleBooking> VehicleBookings => Set<VehicleBooking>();
    public DbSet<ItTicket> ItTickets => Set<ItTicket>();

+    // Phase 11 P11-A (Mig 41) — LevelOpinions 4 module + shared CodeSequence.
+    public DbSet<LeaveRequestLevelOpinion> LeaveRequestLevelOpinions => Set<LeaveRequestLevelOpinion>();
+    public DbSet<OtRequestLevelOpinion> OtRequestLevelOpinions => Set<OtRequestLevelOpinion>();
+    public DbSet<TravelRequestLevelOpinion> TravelRequestLevelOpinions => Set<TravelRequestLevelOpinion>();
+    public DbSet<VehicleBookingLevelOpinion> VehicleBookingLevelOpinions => Set<VehicleBookingLevelOpinion>();
+    public DbSet<WorkflowAppCodeSequence> WorkflowAppCodeSequences => Set<WorkflowAppCodeSequence>();
+
    // Phase 10.4 G-P1 (Mig 40 — S38) — Chấm công web GPS.
    public DbSet<Attendance> Attendances => Set<Attendance>();

--- a/src/Backend/SolutionErp.Infrastructure/Persistence/Configurations/LeaveRequestLevelOpinionConfiguration.cs
+++ b/src/Backend/SolutionErp.Infrastructure/Persistence/Configurations/LeaveRequestLevelOpinionConfiguration.cs
@ -0,0 +1,31 @@
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Metadata.Builders;
+using SolutionErp.Domain.Office;
+
+namespace SolutionErp.Infrastructure.Persistence.Configurations;
+
+// EF Mig 41 P11-A (Phase 11) — Ý kiến cấp duyệt V2 dynamic cho LeaveRequest.
+// Cookie-cutter mirror ProposalLevelOpinionConfiguration (Mig 38).
+public class LeaveRequestLevelOpinionConfiguration : IEntityTypeConfiguration<LeaveRequestLevelOpinion>
+{
+    public void Configure(EntityTypeBuilder<LeaveRequestLevelOpinion> e)
+    {
+        e.ToTable("LeaveRequestLevelOpinions");
+
+        e.Property(x => x.Comment).HasMaxLength(2000);
+        e.Property(x => x.SignedByFullName).HasMaxLength(200).IsRequired();
+
+        e.HasOne(x => x.LeaveRequest)
+            .WithMany(p => p.LevelOpinions)
+            .HasForeignKey(x => x.LeaveRequestId)
+            .OnDelete(DeleteBehavior.Cascade);
+
+        e.HasOne(x => x.Level)
+            .WithMany()
+            .HasForeignKey(x => x.ApprovalWorkflowLevelId)
+            .OnDelete(DeleteBehavior.Restrict);
+
+        e.HasIndex(x => new { x.LeaveRequestId, x.ApprovalWorkflowLevelId }).IsUnique();
+        e.HasIndex(x => x.ApprovalWorkflowLevelId);
+    }
+}
--- a/src/Backend/SolutionErp.Infrastructure/Persistence/Configurations/OtRequestLevelOpinionConfiguration.cs
+++ b/src/Backend/SolutionErp.Infrastructure/Persistence/Configurations/OtRequestLevelOpinionConfiguration.cs
@ -0,0 +1,31 @@
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Metadata.Builders;
+using SolutionErp.Domain.Office;
+
+namespace SolutionErp.Infrastructure.Persistence.Configurations;
+
+// EF Mig 41 P11-A (Phase 11) — Ý kiến cấp duyệt V2 dynamic cho OtRequest.
+// Cookie-cutter mirror ProposalLevelOpinionConfiguration (Mig 38).
+public class OtRequestLevelOpinionConfiguration : IEntityTypeConfiguration<OtRequestLevelOpinion>
+{
+    public void Configure(EntityTypeBuilder<OtRequestLevelOpinion> e)
+    {
+        e.ToTable("OtRequestLevelOpinions");
+
+        e.Property(x => x.Comment).HasMaxLength(2000);
+        e.Property(x => x.SignedByFullName).HasMaxLength(200).IsRequired();
+
+        e.HasOne(x => x.OtRequest)
+            .WithMany(p => p.LevelOpinions)
+            .HasForeignKey(x => x.OtRequestId)
+            .OnDelete(DeleteBehavior.Cascade);
+
+        e.HasOne(x => x.Level)
+            .WithMany()
+            .HasForeignKey(x => x.ApprovalWorkflowLevelId)
+            .OnDelete(DeleteBehavior.Restrict);
+
+        e.HasIndex(x => new { x.OtRequestId, x.ApprovalWorkflowLevelId }).IsUnique();
+        e.HasIndex(x => x.ApprovalWorkflowLevelId);
+    }
+}
--- a/src/Backend/SolutionErp.Infrastructure/Persistence/Configurations/TravelRequestLevelOpinionConfiguration.cs
+++ b/src/Backend/SolutionErp.Infrastructure/Persistence/Configurations/TravelRequestLevelOpinionConfiguration.cs
@ -0,0 +1,31 @@
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Metadata.Builders;
+using SolutionErp.Domain.Office;
+
+namespace SolutionErp.Infrastructure.Persistence.Configurations;
+
+// EF Mig 41 P11-A (Phase 11) — Ý kiến cấp duyệt V2 dynamic cho TravelRequest.
+// Cookie-cutter mirror ProposalLevelOpinionConfiguration (Mig 38).
+public class TravelRequestLevelOpinionConfiguration : IEntityTypeConfiguration<TravelRequestLevelOpinion>
+{
+    public void Configure(EntityTypeBuilder<TravelRequestLevelOpinion> e)
+    {
+        e.ToTable("TravelRequestLevelOpinions");
+
+        e.Property(x => x.Comment).HasMaxLength(2000);
+        e.Property(x => x.SignedByFullName).HasMaxLength(200).IsRequired();
+
+        e.HasOne(x => x.TravelRequest)
+            .WithMany(p => p.LevelOpinions)
+            .HasForeignKey(x => x.TravelRequestId)
+            .OnDelete(DeleteBehavior.Cascade);
+
+        e.HasOne(x => x.Level)
+            .WithMany()
+            .HasForeignKey(x => x.ApprovalWorkflowLevelId)
+            .OnDelete(DeleteBehavior.Restrict);
+
+        e.HasIndex(x => new { x.TravelRequestId, x.ApprovalWorkflowLevelId }).IsUnique();
+        e.HasIndex(x => x.ApprovalWorkflowLevelId);
+    }
+}
--- a/src/Backend/SolutionErp.Infrastructure/Persistence/Configurations/VehicleBookingLevelOpinionConfiguration.cs
+++ b/src/Backend/SolutionErp.Infrastructure/Persistence/Configurations/VehicleBookingLevelOpinionConfiguration.cs
@ -0,0 +1,31 @@
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Metadata.Builders;
+using SolutionErp.Domain.Office;
+
+namespace SolutionErp.Infrastructure.Persistence.Configurations;
+
+// EF Mig 41 P11-A (Phase 11) — Ý kiến cấp duyệt V2 dynamic cho VehicleBooking.
+// Cookie-cutter mirror ProposalLevelOpinionConfiguration (Mig 38).
+public class VehicleBookingLevelOpinionConfiguration : IEntityTypeConfiguration<VehicleBookingLevelOpinion>
+{
+    public void Configure(EntityTypeBuilder<VehicleBookingLevelOpinion> e)
+    {
+        e.ToTable("VehicleBookingLevelOpinions");
+
+        e.Property(x => x.Comment).HasMaxLength(2000);
+        e.Property(x => x.SignedByFullName).HasMaxLength(200).IsRequired();
+
+        e.HasOne(x => x.VehicleBooking)
+            .WithMany(p => p.LevelOpinions)
+            .HasForeignKey(x => x.VehicleBookingId)
+            .OnDelete(DeleteBehavior.Cascade);
+
+        e.HasOne(x => x.Level)
+            .WithMany()
+            .HasForeignKey(x => x.ApprovalWorkflowLevelId)
+            .OnDelete(DeleteBehavior.Restrict);
+
+        e.HasIndex(x => new { x.VehicleBookingId, x.ApprovalWorkflowLevelId }).IsUnique();
+        e.HasIndex(x => x.ApprovalWorkflowLevelId);
+    }
+}
--- a/src/Backend/SolutionErp.Infrastructure/Persistence/Configurations/WorkflowAppCodeSequenceConfiguration.cs
+++ b/src/Backend/SolutionErp.Infrastructure/Persistence/Configurations/WorkflowAppCodeSequenceConfiguration.cs
@ -0,0 +1,19 @@
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Metadata.Builders;
+using SolutionErp.Domain.Office;
+
+namespace SolutionErp.Infrastructure.Persistence.Configurations;
+
+// EF Mig 41 P11-A (Phase 11) — Sequence generator dùng chung cho mã đơn từ 4
+// WorkflowApps module (Leave/OT/Travel/VehicleBooking). Mirror
+// ProposalCodeSequenceConfiguration pattern. PK = Prefix (string), LastSeq atomic.
+public class WorkflowAppCodeSequenceConfiguration : IEntityTypeConfiguration<WorkflowAppCodeSequence>
+{
+    public void Configure(EntityTypeBuilder<WorkflowAppCodeSequence> e)
+    {
+        e.ToTable("WorkflowAppCodeSequences");
+
+        e.HasKey(x => x.Prefix);
+        e.Property(x => x.Prefix).HasMaxLength(20);     // "DT/LR/2026" max ~10 chars OK
+    }
+}
--- a/src/Backend/SolutionErp.Infrastructure/Persistence/DbInitializer.cs
+++ b/src/Backend/SolutionErp.Infrastructure/Persistence/DbInitializer.cs
@ -137,6 +137,13 @@ public static class DbInitializer
        // NOT gated DemoSeed per gotcha #51 INFRASTRUCTURE seed.
        await SeedSampleProposalWorkflowV2Async(db, userManager, logger);

+        // Phase 11 P11-A (S42) — Sample workflow V2 cho 4 WorkflowApps module.
+        // INFRASTRUCTURE seed NOT gated DemoSeed (gotcha #51) — mirror Proposal.
+        await SeedSampleLeaveRequestWorkflowV2Async(db, userManager, logger);
+        await SeedSampleOtRequestWorkflowV2Async(db, userManager, logger);
+        await SeedSampleTravelRequestWorkflowV2Async(db, userManager, logger);
+        await SeedSampleVehicleBookingWorkflowV2Async(db, userManager, logger);
+
        await WarnDefaultAdminPasswordAsync(userManager, logger);
    }

@ -294,6 +301,202 @@ public static class DbInitializer
        logger.LogInformation("Seeded sample ApprovalWorkflow V2 for Proposal: QT-DX-V2-001 v01");
    }

+    // Phase 11 P11-A (S42) — Sample workflow V2 cho 4 WorkflowApps module để UAT
+    // test approval ngay (Leave/OT/Travel/Vehicle). Cookie-cutter mirror
+    // SeedSampleProposalWorkflowV2Async CHÍNH XÁC. INFRASTRUCTURE seed NOT gated
+    // DemoSeed (gotcha #51). Idempotent — skip nếu đã có ANY workflow cùng type.
+    private static async Task SeedSampleLeaveRequestWorkflowV2Async(
+        ApplicationDbContext db, UserManager<User> userManager, ILogger logger)
+    {
+        var hasAny = await db.ApprovalWorkflows
+            .AnyAsync(w => w.ApplicableType == ApprovalWorkflowApplicableType.LeaveRequest);
+        if (hasAny) return;
+
+        var approver = await userManager.FindByEmailAsync("binh.le@solutions.com.vn");
+        if (approver is null)
+        {
+            logger.LogWarning("SeedSampleLeaveRequestWorkflowV2Async: skip — approver binh.le@solutions.com.vn not found");
+            return;
+        }
+
+        var ccmDept = await db.Departments.FirstOrDefaultAsync(d => d.Code == "CCM");
+
+        var wf = new ApprovalWorkflow
+        {
+            Code = "QT-NP-V2-001",
+            Version = 1,
+            ApplicableType = ApprovalWorkflowApplicableType.LeaveRequest,
+            Name = "Quy trình duyệt đơn nghỉ phép (mẫu)",
+            Description = "Sample seed UAT — 1 Bước Phòng CCM × 1 Cấp (Lê Văn Bình). Admin có thể clone tạo version mới qua Designer.",
+            IsActive = true,
+            IsUserSelectable = true,
+            ActivatedAt = DateTime.UtcNow,
+        };
+        var step = new ApprovalWorkflowStep
+        {
+            ApprovalWorkflow = wf,
+            Order = 1,
+            Name = "Cấp duyệt",
+            DepartmentId = ccmDept?.Id,
+        };
+        var level = new ApprovalWorkflowLevel
+        {
+            Step = step,
+            Order = 1,
+            Name = "Cấp 1",
+            ApproverUserId = approver.Id,
+        };
+        wf.Steps.Add(step);
+        step.Levels.Add(level);
+        db.ApprovalWorkflows.Add(wf);
+        await db.SaveChangesAsync();
+        logger.LogInformation("Seeded sample ApprovalWorkflow V2 for LeaveRequest: QT-NP-V2-001 v01");
+    }
+
+    private static async Task SeedSampleOtRequestWorkflowV2Async(
+        ApplicationDbContext db, UserManager<User> userManager, ILogger logger)
+    {
+        var hasAny = await db.ApprovalWorkflows
+            .AnyAsync(w => w.ApplicableType == ApprovalWorkflowApplicableType.OtRequest);
+        if (hasAny) return;
+
+        var approver = await userManager.FindByEmailAsync("binh.le@solutions.com.vn");
+        if (approver is null)
+        {
+            logger.LogWarning("SeedSampleOtRequestWorkflowV2Async: skip — approver binh.le@solutions.com.vn not found");
+            return;
+        }
+
+        var ccmDept = await db.Departments.FirstOrDefaultAsync(d => d.Code == "CCM");
+
+        var wf = new ApprovalWorkflow
+        {
+            Code = "QT-OT-V2-001",
+            Version = 1,
+            ApplicableType = ApprovalWorkflowApplicableType.OtRequest,
+            Name = "Quy trình duyệt đơn OT (mẫu)",
+            Description = "Sample seed UAT — 1 Bước Phòng CCM × 1 Cấp (Lê Văn Bình). Admin có thể clone tạo version mới qua Designer.",
+            IsActive = true,
+            IsUserSelectable = true,
+            ActivatedAt = DateTime.UtcNow,
+        };
+        var step = new ApprovalWorkflowStep
+        {
+            ApprovalWorkflow = wf,
+            Order = 1,
+            Name = "Cấp duyệt",
+            DepartmentId = ccmDept?.Id,
+        };
+        var level = new ApprovalWorkflowLevel
+        {
+            Step = step,
+            Order = 1,
+            Name = "Cấp 1",
+            ApproverUserId = approver.Id,
+        };
+        wf.Steps.Add(step);
+        step.Levels.Add(level);
+        db.ApprovalWorkflows.Add(wf);
+        await db.SaveChangesAsync();
+        logger.LogInformation("Seeded sample ApprovalWorkflow V2 for OtRequest: QT-OT-V2-001 v01");
+    }
+
+    private static async Task SeedSampleTravelRequestWorkflowV2Async(
+        ApplicationDbContext db, UserManager<User> userManager, ILogger logger)
+    {
+        var hasAny = await db.ApprovalWorkflows
+            .AnyAsync(w => w.ApplicableType == ApprovalWorkflowApplicableType.TravelRequest);
+        if (hasAny) return;
+
+        var approver = await userManager.FindByEmailAsync("binh.le@solutions.com.vn");
+        if (approver is null)
+        {
+            logger.LogWarning("SeedSampleTravelRequestWorkflowV2Async: skip — approver binh.le@solutions.com.vn not found");
+            return;
+        }
+
+        var ccmDept = await db.Departments.FirstOrDefaultAsync(d => d.Code == "CCM");
+
+        var wf = new ApprovalWorkflow
+        {
+            Code = "QT-CT-V2-001",
+            Version = 1,
+            ApplicableType = ApprovalWorkflowApplicableType.TravelRequest,
+            Name = "Quy trình duyệt đơn công tác (mẫu)",
+            Description = "Sample seed UAT — 1 Bước Phòng CCM × 1 Cấp (Lê Văn Bình). Admin có thể clone tạo version mới qua Designer.",
+            IsActive = true,
+            IsUserSelectable = true,
+            ActivatedAt = DateTime.UtcNow,
+        };
+        var step = new ApprovalWorkflowStep
+        {
+            ApprovalWorkflow = wf,
+            Order = 1,
+            Name = "Cấp duyệt",
+            DepartmentId = ccmDept?.Id,
+        };
+        var level = new ApprovalWorkflowLevel
+        {
+            Step = step,
+            Order = 1,
+            Name = "Cấp 1",
+            ApproverUserId = approver.Id,
+        };
+        wf.Steps.Add(step);
+        step.Levels.Add(level);
+        db.ApprovalWorkflows.Add(wf);
+        await db.SaveChangesAsync();
+        logger.LogInformation("Seeded sample ApprovalWorkflow V2 for TravelRequest: QT-CT-V2-001 v01");
+    }
+
+    private static async Task SeedSampleVehicleBookingWorkflowV2Async(
+        ApplicationDbContext db, UserManager<User> userManager, ILogger logger)
+    {
+        var hasAny = await db.ApprovalWorkflows
+            .AnyAsync(w => w.ApplicableType == ApprovalWorkflowApplicableType.VehicleBooking);
+        if (hasAny) return;
+
+        var approver = await userManager.FindByEmailAsync("binh.le@solutions.com.vn");
+        if (approver is null)
+        {
+            logger.LogWarning("SeedSampleVehicleBookingWorkflowV2Async: skip — approver binh.le@solutions.com.vn not found");
+            return;
+        }
+
+        var ccmDept = await db.Departments.FirstOrDefaultAsync(d => d.Code == "CCM");
+
+        var wf = new ApprovalWorkflow
+        {
+            Code = "QT-XE-V2-001",
+            Version = 1,
+            ApplicableType = ApprovalWorkflowApplicableType.VehicleBooking,
+            Name = "Quy trình duyệt đặt xe (mẫu)",
+            Description = "Sample seed UAT — 1 Bước Phòng CCM × 1 Cấp (Lê Văn Bình). Admin có thể clone tạo version mới qua Designer.",
+            IsActive = true,
+            IsUserSelectable = true,
+            ActivatedAt = DateTime.UtcNow,
+        };
+        var step = new ApprovalWorkflowStep
+        {
+            ApprovalWorkflow = wf,
+            Order = 1,
+            Name = "Cấp duyệt",
+            DepartmentId = ccmDept?.Id,
+        };
+        var level = new ApprovalWorkflowLevel
+        {
+            Step = step,
+            Order = 1,
+            Name = "Cấp 1",
+            ApproverUserId = approver.Id,
+        };
+        wf.Steps.Add(step);
+        step.Levels.Add(level);
+        db.ApprovalWorkflows.Add(wf);
+        await db.SaveChangesAsync();
+        logger.LogInformation("Seeded sample ApprovalWorkflow V2 for VehicleBooking: QT-XE-V2-001 v01");
+    }
+
    // Seed 4 master catalogs với defaults cho user nhập liệu Details. Idempotent:
    // skip per-table nếu đã có row (admin có thể đã thêm/sửa — không clobber).
    private static async Task SeedCatalogsAsync(ApplicationDbContext db, ILogger logger)
--- a/src/Backend/SolutionErp.Infrastructure/Persistence/Migrations/20260530021936_WireWorkflowAppsApprovalV2.Designer.cs
+++ b/src/Backend/SolutionErp.Infrastructure/Persistence/Migrations/20260530021936_WireWorkflowAppsApprovalV2.Designer.cs
--- a/src/Backend/SolutionErp.Infrastructure/Persistence/Migrations/20260530021936_WireWorkflowAppsApprovalV2.cs
+++ b/src/Backend/SolutionErp.Infrastructure/Persistence/Migrations/20260530021936_WireWorkflowAppsApprovalV2.cs
@ -0,0 +1,275 @@
+using System;
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace SolutionErp.Infrastructure.Persistence.Migrations
+{
+    /// <inheritdoc />
+    public partial class WireWorkflowAppsApprovalV2 : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<int>(
+                name: "RejectedFromStatus",
+                table: "VehicleBookings",
+                type: "int",
+                nullable: true);
+
+            migrationBuilder.AddColumn<int>(
+                name: "RejectedFromStatus",
+                table: "TravelRequests",
+                type: "int",
+                nullable: true);
+
+            migrationBuilder.AddColumn<int>(
+                name: "RejectedFromStatus",
+                table: "OtRequests",
+                type: "int",
+                nullable: true);
+
+            migrationBuilder.AddColumn<int>(
+                name: "RejectedFromStatus",
+                table: "LeaveRequests",
+                type: "int",
+                nullable: true);
+
+            migrationBuilder.CreateTable(
+                name: "LeaveRequestLevelOpinions",
+                columns: table => new
+                {
+                    Id = table.Column<Guid>(type: "uniqueidentifier", nullable: false),
+                    LeaveRequestId = table.Column<Guid>(type: "uniqueidentifier", nullable: false),
+                    ApprovalWorkflowLevelId = table.Column<Guid>(type: "uniqueidentifier", nullable: false),
+                    Comment = table.Column<string>(type: "nvarchar(2000)", maxLength: 2000, nullable: true),
+                    SignedAt = table.Column<DateTime>(type: "datetime2", nullable: false),
+                    SignedByUserId = table.Column<Guid>(type: "uniqueidentifier", nullable: false),
+                    SignedByFullName = table.Column<string>(type: "nvarchar(200)", maxLength: 200, nullable: false),
+                    CreatedAt = table.Column<DateTime>(type: "datetime2", nullable: false),
+                    UpdatedAt = table.Column<DateTime>(type: "datetime2", nullable: true),
+                    CreatedBy = table.Column<Guid>(type: "uniqueidentifier", nullable: true),
+                    UpdatedBy = table.Column<Guid>(type: "uniqueidentifier", nullable: true),
+                    IsDeleted = table.Column<bool>(type: "bit", nullable: false),
+                    DeletedAt = table.Column<DateTime>(type: "datetime2", nullable: true),
+                    DeletedBy = table.Column<Guid>(type: "uniqueidentifier", nullable: true)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_LeaveRequestLevelOpinions", x => x.Id);
+                    table.ForeignKey(
+                        name: "FK_LeaveRequestLevelOpinions_ApprovalWorkflowLevels_ApprovalWorkflowLevelId",
+                        column: x => x.ApprovalWorkflowLevelId,
+                        principalTable: "ApprovalWorkflowLevels",
+                        principalColumn: "Id",
+                        onDelete: ReferentialAction.Restrict);
+                    table.ForeignKey(
+                        name: "FK_LeaveRequestLevelOpinions_LeaveRequests_LeaveRequestId",
+                        column: x => x.LeaveRequestId,
+                        principalTable: "LeaveRequests",
+                        principalColumn: "Id",
+                        onDelete: ReferentialAction.Cascade);
+                });
+
+            migrationBuilder.CreateTable(
+                name: "OtRequestLevelOpinions",
+                columns: table => new
+                {
+                    Id = table.Column<Guid>(type: "uniqueidentifier", nullable: false),
+                    OtRequestId = table.Column<Guid>(type: "uniqueidentifier", nullable: false),
+                    ApprovalWorkflowLevelId = table.Column<Guid>(type: "uniqueidentifier", nullable: false),
+                    Comment = table.Column<string>(type: "nvarchar(2000)", maxLength: 2000, nullable: true),
+                    SignedAt = table.Column<DateTime>(type: "datetime2", nullable: false),
+                    SignedByUserId = table.Column<Guid>(type: "uniqueidentifier", nullable: false),
+                    SignedByFullName = table.Column<string>(type: "nvarchar(200)", maxLength: 200, nullable: false),
+                    CreatedAt = table.Column<DateTime>(type: "datetime2", nullable: false),
+                    UpdatedAt = table.Column<DateTime>(type: "datetime2", nullable: true),
+                    CreatedBy = table.Column<Guid>(type: "uniqueidentifier", nullable: true),
+                    UpdatedBy = table.Column<Guid>(type: "uniqueidentifier", nullable: true),
+                    IsDeleted = table.Column<bool>(type: "bit", nullable: false),
+                    DeletedAt = table.Column<DateTime>(type: "datetime2", nullable: true),
+                    DeletedBy = table.Column<Guid>(type: "uniqueidentifier", nullable: true)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_OtRequestLevelOpinions", x => x.Id);
+                    table.ForeignKey(
+                        name: "FK_OtRequestLevelOpinions_ApprovalWorkflowLevels_ApprovalWorkflowLevelId",
+                        column: x => x.ApprovalWorkflowLevelId,
+                        principalTable: "ApprovalWorkflowLevels",
+                        principalColumn: "Id",
+                        onDelete: ReferentialAction.Restrict);
+                    table.ForeignKey(
+                        name: "FK_OtRequestLevelOpinions_OtRequests_OtRequestId",
+                        column: x => x.OtRequestId,
+                        principalTable: "OtRequests",
+                        principalColumn: "Id",
+                        onDelete: ReferentialAction.Cascade);
+                });
+
+            migrationBuilder.CreateTable(
+                name: "TravelRequestLevelOpinions",
+                columns: table => new
+                {
+                    Id = table.Column<Guid>(type: "uniqueidentifier", nullable: false),
+                    TravelRequestId = table.Column<Guid>(type: "uniqueidentifier", nullable: false),
+                    ApprovalWorkflowLevelId = table.Column<Guid>(type: "uniqueidentifier", nullable: false),
+                    Comment = table.Column<string>(type: "nvarchar(2000)", maxLength: 2000, nullable: true),
+                    SignedAt = table.Column<DateTime>(type: "datetime2", nullable: false),
+                    SignedByUserId = table.Column<Guid>(type: "uniqueidentifier", nullable: false),
+                    SignedByFullName = table.Column<string>(type: "nvarchar(200)", maxLength: 200, nullable: false),
+                    CreatedAt = table.Column<DateTime>(type: "datetime2", nullable: false),
+                    UpdatedAt = table.Column<DateTime>(type: "datetime2", nullable: true),
+                    CreatedBy = table.Column<Guid>(type: "uniqueidentifier", nullable: true),
+                    UpdatedBy = table.Column<Guid>(type: "uniqueidentifier", nullable: true),
+                    IsDeleted = table.Column<bool>(type: "bit", nullable: false),
+                    DeletedAt = table.Column<DateTime>(type: "datetime2", nullable: true),
+                    DeletedBy = table.Column<Guid>(type: "uniqueidentifier", nullable: true)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_TravelRequestLevelOpinions", x => x.Id);
+                    table.ForeignKey(
+                        name: "FK_TravelRequestLevelOpinions_ApprovalWorkflowLevels_ApprovalWorkflowLevelId",
+                        column: x => x.ApprovalWorkflowLevelId,
+                        principalTable: "ApprovalWorkflowLevels",
+                        principalColumn: "Id",
+                        onDelete: ReferentialAction.Restrict);
+                    table.ForeignKey(
+                        name: "FK_TravelRequestLevelOpinions_TravelRequests_TravelRequestId",
+                        column: x => x.TravelRequestId,
+                        principalTable: "TravelRequests",
+                        principalColumn: "Id",
+                        onDelete: ReferentialAction.Cascade);
+                });
+
+            migrationBuilder.CreateTable(
+                name: "VehicleBookingLevelOpinions",
+                columns: table => new
+                {
+                    Id = table.Column<Guid>(type: "uniqueidentifier", nullable: false),
+                    VehicleBookingId = table.Column<Guid>(type: "uniqueidentifier", nullable: false),
+                    ApprovalWorkflowLevelId = table.Column<Guid>(type: "uniqueidentifier", nullable: false),
+                    Comment = table.Column<string>(type: "nvarchar(2000)", maxLength: 2000, nullable: true),
+                    SignedAt = table.Column<DateTime>(type: "datetime2", nullable: false),
+                    SignedByUserId = table.Column<Guid>(type: "uniqueidentifier", nullable: false),
+                    SignedByFullName = table.Column<string>(type: "nvarchar(200)", maxLength: 200, nullable: false),
+                    CreatedAt = table.Column<DateTime>(type: "datetime2", nullable: false),
+                    UpdatedAt = table.Column<DateTime>(type: "datetime2", nullable: true),
+                    CreatedBy = table.Column<Guid>(type: "uniqueidentifier", nullable: true),
+                    UpdatedBy = table.Column<Guid>(type: "uniqueidentifier", nullable: true),
+                    IsDeleted = table.Column<bool>(type: "bit", nullable: false),
+                    DeletedAt = table.Column<DateTime>(type: "datetime2", nullable: true),
+                    DeletedBy = table.Column<Guid>(type: "uniqueidentifier", nullable: true)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_VehicleBookingLevelOpinions", x => x.Id);
+                    table.ForeignKey(
+                        name: "FK_VehicleBookingLevelOpinions_ApprovalWorkflowLevels_ApprovalWorkflowLevelId",
+                        column: x => x.ApprovalWorkflowLevelId,
+                        principalTable: "ApprovalWorkflowLevels",
+                        principalColumn: "Id",
+                        onDelete: ReferentialAction.Restrict);
+                    table.ForeignKey(
+                        name: "FK_VehicleBookingLevelOpinions_VehicleBookings_VehicleBookingId",
+                        column: x => x.VehicleBookingId,
+                        principalTable: "VehicleBookings",
+                        principalColumn: "Id",
+                        onDelete: ReferentialAction.Cascade);
+                });
+
+            migrationBuilder.CreateTable(
+                name: "WorkflowAppCodeSequences",
+                columns: table => new
+                {
+                    Prefix = table.Column<string>(type: "nvarchar(20)", maxLength: 20, nullable: false),
+                    LastSeq = table.Column<int>(type: "int", nullable: false),
+                    UpdatedAt = table.Column<DateTime>(type: "datetime2", nullable: false)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_WorkflowAppCodeSequences", x => x.Prefix);
+                });
+
+            migrationBuilder.CreateIndex(
+                name: "IX_LeaveRequestLevelOpinions_ApprovalWorkflowLevelId",
+                table: "LeaveRequestLevelOpinions",
+                column: "ApprovalWorkflowLevelId");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_LeaveRequestLevelOpinions_LeaveRequestId_ApprovalWorkflowLevelId",
+                table: "LeaveRequestLevelOpinions",
+                columns: new[] { "LeaveRequestId", "ApprovalWorkflowLevelId" },
+                unique: true);
+
+            migrationBuilder.CreateIndex(
+                name: "IX_OtRequestLevelOpinions_ApprovalWorkflowLevelId",
+                table: "OtRequestLevelOpinions",
+                column: "ApprovalWorkflowLevelId");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_OtRequestLevelOpinions_OtRequestId_ApprovalWorkflowLevelId",
+                table: "OtRequestLevelOpinions",
+                columns: new[] { "OtRequestId", "ApprovalWorkflowLevelId" },
+                unique: true);
+
+            migrationBuilder.CreateIndex(
+                name: "IX_TravelRequestLevelOpinions_ApprovalWorkflowLevelId",
+                table: "TravelRequestLevelOpinions",
+                column: "ApprovalWorkflowLevelId");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_TravelRequestLevelOpinions_TravelRequestId_ApprovalWorkflowLevelId",
+                table: "TravelRequestLevelOpinions",
+                columns: new[] { "TravelRequestId", "ApprovalWorkflowLevelId" },
+                unique: true);
+
+            migrationBuilder.CreateIndex(
+                name: "IX_VehicleBookingLevelOpinions_ApprovalWorkflowLevelId",
+                table: "VehicleBookingLevelOpinions",
+                column: "ApprovalWorkflowLevelId");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_VehicleBookingLevelOpinions_VehicleBookingId_ApprovalWorkflowLevelId",
+                table: "VehicleBookingLevelOpinions",
+                columns: new[] { "VehicleBookingId", "ApprovalWorkflowLevelId" },
+                unique: true);
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropTable(
+                name: "LeaveRequestLevelOpinions");
+
+            migrationBuilder.DropTable(
+                name: "OtRequestLevelOpinions");
+
+            migrationBuilder.DropTable(
+                name: "TravelRequestLevelOpinions");
+
+            migrationBuilder.DropTable(
+                name: "VehicleBookingLevelOpinions");
+
+            migrationBuilder.DropTable(
+                name: "WorkflowAppCodeSequences");
+
+            migrationBuilder.DropColumn(
+                name: "RejectedFromStatus",
+                table: "VehicleBookings");
+
+            migrationBuilder.DropColumn(
+                name: "RejectedFromStatus",
+                table: "TravelRequests");
+
+            migrationBuilder.DropColumn(
+                name: "RejectedFromStatus",
+                table: "OtRequests");
+
+            migrationBuilder.DropColumn(
+                name: "RejectedFromStatus",
+                table: "LeaveRequests");
+        }
+    }
+}
--- a/src/Backend/SolutionErp.Infrastructure/Persistence/Migrations/ApplicationDbContextModelSnapshot.cs
+++ b/src/Backend/SolutionErp.Infrastructure/Persistence/Migrations/ApplicationDbContextModelSnapshot.cs
@ -3676,6 +3676,9 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
                        .HasMaxLength(1000)
                        .HasColumnType("nvarchar(1000)");

+                    b.Property<int?>("RejectedFromStatus")
+                        .HasColumnType("int");
+
                    b.Property<string>("RequesterFullName")
                        .IsRequired()
                        .HasMaxLength(200)
@ -3709,6 +3712,64 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
                    b.ToTable("LeaveRequests", (string)null);
                });

+            modelBuilder.Entity("SolutionErp.Domain.Office.LeaveRequestLevelOpinion", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<Guid>("ApprovalWorkflowLevelId")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<string>("Comment")
+                        .HasMaxLength(2000)
+                        .HasColumnType("nvarchar(2000)");
+
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("datetime2");
+
+                    b.Property<Guid?>("CreatedBy")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<DateTime?>("DeletedAt")
+                        .HasColumnType("datetime2");
+
+                    b.Property<Guid?>("DeletedBy")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<bool>("IsDeleted")
+                        .HasColumnType("bit");
+
+                    b.Property<Guid>("LeaveRequestId")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<DateTime>("SignedAt")
+                        .HasColumnType("datetime2");
+
+                    b.Property<string>("SignedByFullName")
+                        .IsRequired()
+                        .HasMaxLength(200)
+                        .HasColumnType("nvarchar(200)");
+
+                    b.Property<Guid>("SignedByUserId")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<DateTime?>("UpdatedAt")
+                        .HasColumnType("datetime2");
+
+                    b.Property<Guid?>("UpdatedBy")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("ApprovalWorkflowLevelId");
+
+                    b.HasIndex("LeaveRequestId", "ApprovalWorkflowLevelId")
+                        .IsUnique();
+
+                    b.ToTable("LeaveRequestLevelOpinions", (string)null);
+                });
+
            modelBuilder.Entity("SolutionErp.Domain.Office.MeetingBooking", b =>
                {
                    b.Property<Guid>("Id")
@ -3932,6 +3993,9 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
                        .HasMaxLength(1000)
                        .HasColumnType("nvarchar(1000)");

+                    b.Property<int?>("RejectedFromStatus")
+                        .HasColumnType("int");
+
                    b.Property<string>("RequesterFullName")
                        .IsRequired()
                        .HasMaxLength(200)
@ -3965,6 +4029,64 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
                    b.ToTable("OtRequests", (string)null);
                });

+            modelBuilder.Entity("SolutionErp.Domain.Office.OtRequestLevelOpinion", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<Guid>("ApprovalWorkflowLevelId")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<string>("Comment")
+                        .HasMaxLength(2000)
+                        .HasColumnType("nvarchar(2000)");
+
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("datetime2");
+
+                    b.Property<Guid?>("CreatedBy")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<DateTime?>("DeletedAt")
+                        .HasColumnType("datetime2");
+
+                    b.Property<Guid?>("DeletedBy")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<bool>("IsDeleted")
+                        .HasColumnType("bit");
+
+                    b.Property<Guid>("OtRequestId")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<DateTime>("SignedAt")
+                        .HasColumnType("datetime2");
+
+                    b.Property<string>("SignedByFullName")
+                        .IsRequired()
+                        .HasMaxLength(200)
+                        .HasColumnType("nvarchar(200)");
+
+                    b.Property<Guid>("SignedByUserId")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<DateTime?>("UpdatedAt")
+                        .HasColumnType("datetime2");
+
+                    b.Property<Guid?>("UpdatedBy")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("ApprovalWorkflowLevelId");
+
+                    b.HasIndex("OtRequestId", "ApprovalWorkflowLevelId")
+                        .IsUnique();
+
+                    b.ToTable("OtRequestLevelOpinions", (string)null);
+                });
+
            modelBuilder.Entity("SolutionErp.Domain.Office.Proposal", b =>
                {
                    b.Property<Guid>("Id")
@ -4236,6 +4358,9 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
                        .HasMaxLength(1000)
                        .HasColumnType("nvarchar(1000)");

+                    b.Property<int?>("RejectedFromStatus")
+                        .HasColumnType("int");
+
                    b.Property<string>("RequesterFullName")
                        .IsRequired()
                        .HasMaxLength(200)
@ -4269,6 +4394,64 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
                    b.ToTable("TravelRequests", (string)null);
                });

+            modelBuilder.Entity("SolutionErp.Domain.Office.TravelRequestLevelOpinion", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<Guid>("ApprovalWorkflowLevelId")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<string>("Comment")
+                        .HasMaxLength(2000)
+                        .HasColumnType("nvarchar(2000)");
+
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("datetime2");
+
+                    b.Property<Guid?>("CreatedBy")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<DateTime?>("DeletedAt")
+                        .HasColumnType("datetime2");
+
+                    b.Property<Guid?>("DeletedBy")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<bool>("IsDeleted")
+                        .HasColumnType("bit");
+
+                    b.Property<DateTime>("SignedAt")
+                        .HasColumnType("datetime2");
+
+                    b.Property<string>("SignedByFullName")
+                        .IsRequired()
+                        .HasMaxLength(200)
+                        .HasColumnType("nvarchar(200)");
+
+                    b.Property<Guid>("SignedByUserId")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<Guid>("TravelRequestId")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<DateTime?>("UpdatedAt")
+                        .HasColumnType("datetime2");
+
+                    b.Property<Guid?>("UpdatedBy")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("ApprovalWorkflowLevelId");
+
+                    b.HasIndex("TravelRequestId", "ApprovalWorkflowLevelId")
+                        .IsUnique();
+
+                    b.ToTable("TravelRequestLevelOpinions", (string)null);
+                });
+
            modelBuilder.Entity("SolutionErp.Domain.Office.VehicleBooking", b =>
                {
                    b.Property<Guid>("Id")
@ -4317,6 +4500,9 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
                        .HasMaxLength(1000)
                        .HasColumnType("nvarchar(1000)");

+                    b.Property<int?>("RejectedFromStatus")
+                        .HasColumnType("int");
+
                    b.Property<string>("RequesterFullName")
                        .IsRequired()
                        .HasMaxLength(200)
@ -4361,6 +4547,81 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
                    b.ToTable("VehicleBookings", (string)null);
                });

+            modelBuilder.Entity("SolutionErp.Domain.Office.VehicleBookingLevelOpinion", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<Guid>("ApprovalWorkflowLevelId")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<string>("Comment")
+                        .HasMaxLength(2000)
+                        .HasColumnType("nvarchar(2000)");
+
+                    b.Property<DateTime>("CreatedAt")
+                        .HasColumnType("datetime2");
+
+                    b.Property<Guid?>("CreatedBy")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<DateTime?>("DeletedAt")
+                        .HasColumnType("datetime2");
+
+                    b.Property<Guid?>("DeletedBy")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<bool>("IsDeleted")
+                        .HasColumnType("bit");
+
+                    b.Property<DateTime>("SignedAt")
+                        .HasColumnType("datetime2");
+
+                    b.Property<string>("SignedByFullName")
+                        .IsRequired()
+                        .HasMaxLength(200)
+                        .HasColumnType("nvarchar(200)");
+
+                    b.Property<Guid>("SignedByUserId")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<DateTime?>("UpdatedAt")
+                        .HasColumnType("datetime2");
+
+                    b.Property<Guid?>("UpdatedBy")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.Property<Guid>("VehicleBookingId")
+                        .HasColumnType("uniqueidentifier");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("ApprovalWorkflowLevelId");
+
+                    b.HasIndex("VehicleBookingId", "ApprovalWorkflowLevelId")
+                        .IsUnique();
+
+                    b.ToTable("VehicleBookingLevelOpinions", (string)null);
+                });
+
+            modelBuilder.Entity("SolutionErp.Domain.Office.WorkflowAppCodeSequence", b =>
+                {
+                    b.Property<string>("Prefix")
+                        .HasMaxLength(20)
+                        .HasColumnType("nvarchar(20)");
+
+                    b.Property<int>("LastSeq")
+                        .HasColumnType("int");
+
+                    b.Property<DateTime>("UpdatedAt")
+                        .HasColumnType("datetime2");
+
+                    b.HasKey("Prefix");
+
+                    b.ToTable("WorkflowAppCodeSequences", (string)null);
+                });
+
            modelBuilder.Entity("SolutionErp.Domain.PurchaseEvaluations.PurchaseEvaluation", b =>
                {
                    b.Property<Guid>("Id")
@ -5603,6 +5864,25 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
                        .OnDelete(DeleteBehavior.Restrict);
                });

+            modelBuilder.Entity("SolutionErp.Domain.Office.LeaveRequestLevelOpinion", b =>
+                {
+                    b.HasOne("SolutionErp.Domain.ApprovalWorkflowsV2.ApprovalWorkflowLevel", "Level")
+                        .WithMany()
+                        .HasForeignKey("ApprovalWorkflowLevelId")
+                        .OnDelete(DeleteBehavior.Restrict)
+                        .IsRequired();
+
+                    b.HasOne("SolutionErp.Domain.Office.LeaveRequest", "LeaveRequest")
+                        .WithMany("LevelOpinions")
+                        .HasForeignKey("LeaveRequestId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("LeaveRequest");
+
+                    b.Navigation("Level");
+                });
+
            modelBuilder.Entity("SolutionErp.Domain.Office.MeetingBooking", b =>
                {
                    b.HasOne("SolutionErp.Domain.Office.MeetingRoom", "Room")
@ -5625,6 +5905,25 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
                    b.Navigation("Booking");
                });

+            modelBuilder.Entity("SolutionErp.Domain.Office.OtRequestLevelOpinion", b =>
+                {
+                    b.HasOne("SolutionErp.Domain.ApprovalWorkflowsV2.ApprovalWorkflowLevel", "Level")
+                        .WithMany()
+                        .HasForeignKey("ApprovalWorkflowLevelId")
+                        .OnDelete(DeleteBehavior.Restrict)
+                        .IsRequired();
+
+                    b.HasOne("SolutionErp.Domain.Office.OtRequest", "OtRequest")
+                        .WithMany("LevelOpinions")
+                        .HasForeignKey("OtRequestId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("Level");
+
+                    b.Navigation("OtRequest");
+                });
+
            modelBuilder.Entity("SolutionErp.Domain.Office.ProposalAttachment", b =>
                {
                    b.HasOne("SolutionErp.Domain.Office.Proposal", "Proposal")
@ -5655,6 +5954,44 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
                    b.Navigation("Proposal");
                });

+            modelBuilder.Entity("SolutionErp.Domain.Office.TravelRequestLevelOpinion", b =>
+                {
+                    b.HasOne("SolutionErp.Domain.ApprovalWorkflowsV2.ApprovalWorkflowLevel", "Level")
+                        .WithMany()
+                        .HasForeignKey("ApprovalWorkflowLevelId")
+                        .OnDelete(DeleteBehavior.Restrict)
+                        .IsRequired();
+
+                    b.HasOne("SolutionErp.Domain.Office.TravelRequest", "TravelRequest")
+                        .WithMany("LevelOpinions")
+                        .HasForeignKey("TravelRequestId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("Level");
+
+                    b.Navigation("TravelRequest");
+                });
+
+            modelBuilder.Entity("SolutionErp.Domain.Office.VehicleBookingLevelOpinion", b =>
+                {
+                    b.HasOne("SolutionErp.Domain.ApprovalWorkflowsV2.ApprovalWorkflowLevel", "Level")
+                        .WithMany()
+                        .HasForeignKey("ApprovalWorkflowLevelId")
+                        .OnDelete(DeleteBehavior.Restrict)
+                        .IsRequired();
+
+                    b.HasOne("SolutionErp.Domain.Office.VehicleBooking", "VehicleBooking")
+                        .WithMany("LevelOpinions")
+                        .HasForeignKey("VehicleBookingId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("Level");
+
+                    b.Navigation("VehicleBooking");
+                });
+
            modelBuilder.Entity("SolutionErp.Domain.PurchaseEvaluations.PurchaseEvaluation", b =>
                {
                    b.HasOne("SolutionErp.Domain.ApprovalWorkflowsV2.ApprovalWorkflow", null)
@ -5889,11 +6226,21 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
                    b.Navigation("Permissions");
                });

+            modelBuilder.Entity("SolutionErp.Domain.Office.LeaveRequest", b =>
+                {
+                    b.Navigation("LevelOpinions");
+                });
+
            modelBuilder.Entity("SolutionErp.Domain.Office.MeetingBooking", b =>
                {
                    b.Navigation("Attendees");
                });

+            modelBuilder.Entity("SolutionErp.Domain.Office.OtRequest", b =>
+                {
+                    b.Navigation("LevelOpinions");
+                });
+
            modelBuilder.Entity("SolutionErp.Domain.Office.Proposal", b =>
                {
                    b.Navigation("Attachments");
@ -5901,6 +6248,16 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
                    b.Navigation("LevelOpinions");
                });

+            modelBuilder.Entity("SolutionErp.Domain.Office.TravelRequest", b =>
+                {
+                    b.Navigation("LevelOpinions");
+                });
+
+            modelBuilder.Entity("SolutionErp.Domain.Office.VehicleBooking", b =>
+                {
+                    b.Navigation("LevelOpinions");
+                });
+
            modelBuilder.Entity("SolutionErp.Domain.PurchaseEvaluations.PurchaseEvaluation", b =>
                {
                    b.Navigation("Approvals");
--- a/tests/SolutionErp.Infrastructure.Tests/Application/WorkflowAppApproveV2Tests.cs
+++ b/tests/SolutionErp.Infrastructure.Tests/Application/WorkflowAppApproveV2Tests.cs
@ -0,0 +1,443 @@
+using Microsoft.AspNetCore.Identity;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.DependencyInjection;
+using SolutionErp.Application.Common.Exceptions;
+using SolutionErp.Application.Office;
+using SolutionErp.Domain.ApprovalWorkflowsV2;
+using SolutionErp.Domain.Identity;
+using SolutionErp.Domain.Office;
+using SolutionErp.Infrastructure.Tests.Common;
+
+namespace SolutionErp.Infrastructure.Tests.Application;
+
+// Phase 11 P11-A Wave 4 (S42 2026-05-30) — test-after ApproveV2 wire WorkflowApps.
+// Critical-algo state machine + UPSERT invariant cho LeaveOtApprovalFeatures.cs
+// (LeaveRequest đầy đủ 8 case + OtRequest smoke 1 case).
+//
+// Handlers là CQRS MediatR — inject IApplicationDbContext + ICurrentUser + IDateTime
+// trực tiếp (không qua service). Khác ContractWorkflowServiceApproveV2Tests (service
+// wire 6 dep) — đây nhẹ hơn, instantiate handler + gọi Handle().
+//
+// Mirror LeaveOtApprovalFeatures.cs:250 ApproveLeaveRequestHandler. Status state:
+//   Nhap=1, DaGuiDuyet=2, TraLai=3, TuChoi=4, DaDuyet=5.
+// LevelOpinion UNIQUE composite (LeaveRequestId, ApprovalWorkflowLevelId).
+public class WorkflowAppApproveV2Tests
+{
+    private static readonly DateTime FixedNow = new(2026, 5, 30, 8, 0, 0, DateTimeKind.Utc);
+
+    private static (IdentityFixture fix, TestApplicationDbContext db, FixedDateTime clock) NewCtx()
+    {
+        var fix = new IdentityFixture();
+        var db = fix.Services.GetRequiredService<TestApplicationDbContext>();
+        var clock = new FixedDateTime(FixedNow);
+        return (fix, db, clock);
+    }
+
+    private static TestCurrentUser AsUser(User u, params string[] roles)
+        => new() { UserId = u.Id, FullName = u.FullName, Roles = roles ?? Array.Empty<string>() };
+
+    // Seed 1 Bước × N Cấp LeaveRequest workflow. Trả về list Levels theo Order asc.
+    private static async Task<(ApprovalWorkflow wf, List<ApprovalWorkflowLevel> levels)> SeedLeaveWorkflowAsync(
+        TestApplicationDbContext db, params Guid[] approverUserIds)
+    {
+        var wf = new ApprovalWorkflow
+        {
+            Id = Guid.NewGuid(),
+            Code = "QT-LR-001",
+            Version = 1,
+            Name = "Quy trình nghỉ phép test",
+            ApplicableType = ApprovalWorkflowApplicableType.LeaveRequest,
+            IsActive = true,
+            IsUserSelectable = true,
+        };
+        var step = new ApprovalWorkflowStep
+        {
+            Id = Guid.NewGuid(),
+            ApprovalWorkflowId = wf.Id,
+            Order = 1,
+            DepartmentId = null,
+            Name = "Bước 1",
+        };
+        var levels = new List<ApprovalWorkflowLevel>();
+        for (var i = 0; i < approverUserIds.Length; i++)
+        {
+            levels.Add(new ApprovalWorkflowLevel
+            {
+                Id = Guid.NewGuid(),
+                ApprovalWorkflowStepId = step.Id,
+                Order = i + 1,
+                ApproverUserId = approverUserIds[i],
+            });
+        }
+        db.ApprovalWorkflows.Add(wf);
+        db.ApprovalWorkflowSteps.Add(step);
+        db.ApprovalWorkflowLevels.AddRange(levels);
+        await db.SaveChangesAsync(CancellationToken.None);
+        return (wf, levels);
+    }
+
+    private static LeaveRequest BuildLeave(
+        Guid requesterId,
+        Guid? workflowId,
+        WorkflowAppStatus status,
+        int? currentLevel)
+        => new()
+        {
+            Id = Guid.NewGuid(),
+            RequesterUserId = requesterId,
+            RequesterFullName = "Người tạo",
+            LeaveTypeId = Guid.NewGuid(),
+            StartDate = FixedNow.Date,
+            EndDate = FixedNow.Date.AddDays(2),
+            NumDays = 3,
+            Reason = "Nghỉ việc riêng",
+            Status = status,
+            ApprovalWorkflowId = workflowId,
+            CurrentApprovalLevelOrder = currentLevel,
+        };
+
+    // ============ Case 1: Submit happy path ============
+
+    [Fact]
+    public async Task Submit_FromNhap_AdvancesToDaGuiDuyet_GeneratesMaDonTu()
+    {
+        var (fix, db, clock) = NewCtx();
+        using (fix)
+        {
+            var requester = await fix.CreateUserAsync("req-c1@test.local", "Requester", null, Array.Empty<string>());
+            var approver = await fix.CreateUserAsync("ap-c1@test.local", "Approver", null, Array.Empty<string>());
+            var (wf, _) = await SeedLeaveWorkflowAsync(db, approver.Id);
+
+            var leave = BuildLeave(requester.Id, wf.Id, WorkflowAppStatus.Nhap, currentLevel: null);
+            db.LeaveRequests.Add(leave);
+            await db.SaveChangesAsync(CancellationToken.None);
+
+            var handler = new SubmitLeaveRequestHandler(db, AsUser(requester), clock);
+            await handler.Handle(new SubmitLeaveRequestCommand(leave.Id), CancellationToken.None);
+
+            leave.Status.Should().Be(WorkflowAppStatus.DaGuiDuyet);
+            leave.CurrentApprovalLevelOrder.Should().Be(1);
+            leave.RejectedFromStatus.Should().BeNull();
+            leave.MaDonTu.Should().NotBeNullOrEmpty();
+            leave.MaDonTu.Should().Be("DT/LR/2026/001", "prefix DT/LR + năm clock + seq D3");
+
+            var seq = await db.WorkflowAppCodeSequences.FirstAsync(s => s.Prefix == "DT/LR/2026");
+            seq.LastSeq.Should().Be(1);
+        }
+    }
+
+    // ============ Case 2: Submit guards ============
+
+    [Fact]
+    public async Task Submit_WhenStatusNotNhapOrTraLai_ThrowsConflict()
+    {
+        var (fix, db, clock) = NewCtx();
+        using (fix)
+        {
+            var requester = await fix.CreateUserAsync("req-c2a@test.local", "Requester", null, Array.Empty<string>());
+            var approver = await fix.CreateUserAsync("ap-c2a@test.local", "Approver", null, Array.Empty<string>());
+            var (wf, _) = await SeedLeaveWorkflowAsync(db, approver.Id);
+
+            var leave = BuildLeave(requester.Id, wf.Id, WorkflowAppStatus.DaGuiDuyet, currentLevel: 1);
+            db.LeaveRequests.Add(leave);
+            await db.SaveChangesAsync(CancellationToken.None);
+
+            var handler = new SubmitLeaveRequestHandler(db, AsUser(requester), clock);
+            var act = async () => await handler.Handle(new SubmitLeaveRequestCommand(leave.Id), CancellationToken.None);
+
+            await act.Should().ThrowAsync<ConflictException>().WithMessage("*Nháp hoặc Trả lại*");
+        }
+    }
+
+    [Fact]
+    public async Task Submit_WhenApprovalWorkflowIdNull_ThrowsConflict()
+    {
+        var (fix, db, clock) = NewCtx();
+        using (fix)
+        {
+            var requester = await fix.CreateUserAsync("req-c2b@test.local", "Requester", null, Array.Empty<string>());
+
+            var leave = BuildLeave(requester.Id, workflowId: null, WorkflowAppStatus.Nhap, currentLevel: null);
+            db.LeaveRequests.Add(leave);
+            await db.SaveChangesAsync(CancellationToken.None);
+
+            var handler = new SubmitLeaveRequestHandler(db, AsUser(requester), clock);
+            var act = async () => await handler.Handle(new SubmitLeaveRequestCommand(leave.Id), CancellationToken.None);
+
+            await act.Should().ThrowAsync<ConflictException>().WithMessage("*Chưa chọn quy trình duyệt*");
+        }
+    }
+
+    // ============ Case 3: Approve advance (2-level, cấp 1) ============
+
+    [Fact]
+    public async Task Approve_FirstLevel_TwoLevel_AdvancesAndCreatesOneOpinion()
+    {
+        var (fix, db, clock) = NewCtx();
+        using (fix)
+        {
+            var requester = await fix.CreateUserAsync("req-c3@test.local", "Requester", null, Array.Empty<string>());
+            var ap1 = await fix.CreateUserAsync("ap1-c3@test.local", "Approver 1", null, Array.Empty<string>());
+            var ap2 = await fix.CreateUserAsync("ap2-c3@test.local", "Approver 2", null, Array.Empty<string>());
+            var (wf, levels) = await SeedLeaveWorkflowAsync(db, ap1.Id, ap2.Id);
+
+            var leave = BuildLeave(requester.Id, wf.Id, WorkflowAppStatus.DaGuiDuyet, currentLevel: 1);
+            db.LeaveRequests.Add(leave);
+            await db.SaveChangesAsync(CancellationToken.None);
+
+            var handler = new ApproveLeaveRequestHandler(db, AsUser(ap1), clock);
+            await handler.Handle(new ApproveLeaveRequestCommand(leave.Id, "đồng ý"), CancellationToken.None);
+
+            leave.Status.Should().Be(WorkflowAppStatus.DaGuiDuyet, "còn Cấp 2 chưa terminal");
+            leave.CurrentApprovalLevelOrder.Should().Be(2);
+
+            var opinions = await db.LeaveRequestLevelOpinions.Where(o => o.LeaveRequestId == leave.Id).ToListAsync();
+            opinions.Should().HaveCount(1);
+            opinions[0].ApprovalWorkflowLevelId.Should().Be(levels[0].Id, "slot Cấp 1");
+            opinions[0].Comment.Should().Be("đồng ý");
+            opinions[0].SignedByUserId.Should().Be(ap1.Id);
+        }
+    }
+
+    // ============ Case 4: Approve terminal (cấp cuối) ============
+
+    [Fact]
+    public async Task Approve_LastLevel_TransitionsToDaDuyet_ClearsCurrentLevel()
+    {
+        var (fix, db, clock) = NewCtx();
+        using (fix)
+        {
+            var requester = await fix.CreateUserAsync("req-c4@test.local", "Requester", null, Array.Empty<string>());
+            var ap1 = await fix.CreateUserAsync("ap1-c4@test.local", "Approver 1", null, Array.Empty<string>());
+            var ap2 = await fix.CreateUserAsync("ap2-c4@test.local", "Approver 2", null, Array.Empty<string>());
+            var (wf, _) = await SeedLeaveWorkflowAsync(db, ap1.Id, ap2.Id);
+
+            // pin tại Cấp cuối (2)
+            var leave = BuildLeave(requester.Id, wf.Id, WorkflowAppStatus.DaGuiDuyet, currentLevel: 2);
+            db.LeaveRequests.Add(leave);
+            await db.SaveChangesAsync(CancellationToken.None);
+
+            var handler = new ApproveLeaveRequestHandler(db, AsUser(ap2), clock);
+            await handler.Handle(new ApproveLeaveRequestCommand(leave.Id, "duyệt cuối"), CancellationToken.None);
+
+            leave.Status.Should().Be(WorkflowAppStatus.DaDuyet, "Cấp cuối → terminal");
+            leave.CurrentApprovalLevelOrder.Should().BeNull();
+
+            var opinions = await db.LeaveRequestLevelOpinions.Where(o => o.LeaveRequestId == leave.Id).ToListAsync();
+            opinions.Should().HaveCount(1, "1 row cho slot Cấp 2");
+        }
+    }
+
+    // ============ Case 5: Approve UPSERT invariant (re-sign same level) ============
+
+    [Fact]
+    public async Task Approve_SameLevelTwice_AdminReSign_DoesNotDuplicateRow_UpdatesLatestWrite()
+    {
+        var (fix, db, clock) = NewCtx();
+        using (fix)
+        {
+            var requester = await fix.CreateUserAsync("req-c5@test.local", "Requester", null, Array.Empty<string>());
+            var ap1 = await fix.CreateUserAsync("ap1-c5@test.local", "Approver 1", null, Array.Empty<string>());
+            var ap2 = await fix.CreateUserAsync("ap2-c5@test.local", "Approver 2", null, Array.Empty<string>());
+            var admin = await fix.CreateUserAsync("admin-c5@test.local", "Quản trị", null, new[] { "Admin" });
+            var (wf, levels) = await SeedLeaveWorkflowAsync(db, ap1.Id, ap2.Id);
+
+            var leave = BuildLeave(requester.Id, wf.Id, WorkflowAppStatus.DaGuiDuyet, currentLevel: 1);
+            db.LeaveRequests.Add(leave);
+            await db.SaveChangesAsync(CancellationToken.None);
+
+            // 1st approve Cấp 1 bởi ap1 → tạo row, advance lên Cấp 2
+            await new ApproveLeaveRequestHandler(db, AsUser(ap1), clock)
+                .Handle(new ApproveLeaveRequestCommand(leave.Id, "ý kiến gốc"), CancellationToken.None);
+            leave.CurrentApprovalLevelOrder.Should().Be(2);
+
+            // Admin override re-sign Cấp 1: pin pointer trở lại Cấp 1 + admin duyệt lại
+            leave.CurrentApprovalLevelOrder = 1;
+            await db.SaveChangesAsync(CancellationToken.None);
+            await new ApproveLeaveRequestHandler(db, AsUser(admin, "Admin"), clock)
+                .Handle(new ApproveLeaveRequestCommand(leave.Id, "admin ký lại"), CancellationToken.None);
+
+            var opinions = await db.LeaveRequestLevelOpinions
+                .Where(o => o.LeaveRequestId == leave.Id && o.ApprovalWorkflowLevelId == levels[0].Id)
+                .ToListAsync();
+            opinions.Should().HaveCount(1, "UNIQUE composite — KHÔNG tạo row thứ 2");
+            opinions[0].Comment.Should().Be("admin ký lại", "latest-write-wins");
+            opinions[0].SignedByUserId.Should().Be(admin.Id, "signer cập nhật người ký mới nhất");
+        }
+    }
+
+    // ============ Case 6: Approve forbidden (outsider non-admin) ============
+
+    [Fact]
+    public async Task Approve_OutsiderNonAdmin_ThrowsForbidden_StateUnchanged()
+    {
+        var (fix, db, clock) = NewCtx();
+        using (fix)
+        {
+            var requester = await fix.CreateUserAsync("req-c6@test.local", "Requester", null, Array.Empty<string>());
+            var ap1 = await fix.CreateUserAsync("ap1-c6@test.local", "Approver 1", null, Array.Empty<string>());
+            var outsider = await fix.CreateUserAsync("out-c6@test.local", "Outsider", null, Array.Empty<string>());
+            var (wf, _) = await SeedLeaveWorkflowAsync(db, ap1.Id);
+
+            var leave = BuildLeave(requester.Id, wf.Id, WorkflowAppStatus.DaGuiDuyet, currentLevel: 1);
+            db.LeaveRequests.Add(leave);
+            await db.SaveChangesAsync(CancellationToken.None);
+
+            var handler = new ApproveLeaveRequestHandler(db, AsUser(outsider), clock);
+            var act = async () => await handler.Handle(new ApproveLeaveRequestCommand(leave.Id, "thử duyệt"), CancellationToken.None);
+
+            await act.Should().ThrowAsync<ForbiddenException>().WithMessage("*Không phải người duyệt*");
+            leave.Status.Should().Be(WorkflowAppStatus.DaGuiDuyet, "guard chặn trước mutate");
+            leave.CurrentApprovalLevelOrder.Should().Be(1);
+            (await db.LeaveRequestLevelOpinions.CountAsync(o => o.LeaveRequestId == leave.Id))
+                .Should().Be(0, "không tạo opinion khi bị chặn");
+        }
+    }
+
+    // ============ Case 7: Approve empty comment → placeholder ============
+
+    [Fact]
+    public async Task Approve_EmptyComment_StoresPlaceholder()
+    {
+        var (fix, db, clock) = NewCtx();
+        using (fix)
+        {
+            var requester = await fix.CreateUserAsync("req-c7@test.local", "Requester", null, Array.Empty<string>());
+            var ap1 = await fix.CreateUserAsync("ap1-c7@test.local", "Approver 1", null, Array.Empty<string>());
+            var (wf, levels) = await SeedLeaveWorkflowAsync(db, ap1.Id);
+
+            var leave = BuildLeave(requester.Id, wf.Id, WorkflowAppStatus.DaGuiDuyet, currentLevel: 1);
+            db.LeaveRequests.Add(leave);
+            await db.SaveChangesAsync(CancellationToken.None);
+
+            await new ApproveLeaveRequestHandler(db, AsUser(ap1), clock)
+                .Handle(new ApproveLeaveRequestCommand(leave.Id, "   "), CancellationToken.None);
+
+            var opinion = await db.LeaveRequestLevelOpinions
+                .FirstAsync(o => o.LeaveRequestId == leave.Id && o.ApprovalWorkflowLevelId == levels[0].Id);
+            opinion.Comment.Should().Be("(duyệt — không ý kiến)");
+        }
+    }
+
+    // ============ Case 8a: Reject → TuChoi ============
+
+    [Fact]
+    public async Task Reject_FromDaGuiDuyet_TransitionsToTuChoi_ClearsCurrentLevel()
+    {
+        var (fix, db, clock) = NewCtx();
+        using (fix)
+        {
+            var requester = await fix.CreateUserAsync("req-c8a@test.local", "Requester", null, Array.Empty<string>());
+            var ap1 = await fix.CreateUserAsync("ap1-c8a@test.local", "Approver 1", null, Array.Empty<string>());
+            var (wf, _) = await SeedLeaveWorkflowAsync(db, ap1.Id);
+
+            var leave = BuildLeave(requester.Id, wf.Id, WorkflowAppStatus.DaGuiDuyet, currentLevel: 1);
+            db.LeaveRequests.Add(leave);
+            await db.SaveChangesAsync(CancellationToken.None);
+
+            await new RejectLeaveRequestHandler(db, AsUser(ap1), clock)
+                .Handle(new RejectLeaveRequestCommand(leave.Id, "không duyệt"), CancellationToken.None);
+
+            leave.Status.Should().Be(WorkflowAppStatus.TuChoi);
+            leave.CurrentApprovalLevelOrder.Should().BeNull();
+        }
+    }
+
+    // ============ Case 8b: Return → TraLai + RejectedFromStatus ============
+
+    [Fact]
+    public async Task Return_FromDaGuiDuyet_TransitionsToTraLai_SetsRejectedFromStatus()
+    {
+        var (fix, db, clock) = NewCtx();
+        using (fix)
+        {
+            var requester = await fix.CreateUserAsync("req-c8b@test.local", "Requester", null, Array.Empty<string>());
+            var ap1 = await fix.CreateUserAsync("ap1-c8b@test.local", "Approver 1", null, Array.Empty<string>());
+            var (wf, _) = await SeedLeaveWorkflowAsync(db, ap1.Id);
+
+            var leave = BuildLeave(requester.Id, wf.Id, WorkflowAppStatus.DaGuiDuyet, currentLevel: 1);
+            db.LeaveRequests.Add(leave);
+            await db.SaveChangesAsync(CancellationToken.None);
+
+            await new ReturnLeaveRequestHandler(db, AsUser(ap1), clock)
+                .Handle(new ReturnLeaveRequestCommand(leave.Id, "sửa lại"), CancellationToken.None);
+
+            leave.Status.Should().Be(WorkflowAppStatus.TraLai);
+            leave.RejectedFromStatus.Should().Be(WorkflowAppStatus.DaGuiDuyet);
+            leave.CurrentApprovalLevelOrder.Should().BeNull();
+        }
+    }
+
+    // ============ Smoke OtRequest: mirror cookie-cutter — terminal happy path ============
+
+    [Fact]
+    public async Task OtRequest_Submit_Then_Approve_SingleLevel_ReachesDaDuyet()
+    {
+        var (fix, db, clock) = NewCtx();
+        using (fix)
+        {
+            var requester = await fix.CreateUserAsync("req-ot@test.local", "Requester", null, Array.Empty<string>());
+            var approver = await fix.CreateUserAsync("ap-ot@test.local", "Approver", null, Array.Empty<string>());
+
+            var wf = new ApprovalWorkflow
+            {
+                Id = Guid.NewGuid(),
+                Code = "QT-OT-001",
+                Version = 1,
+                Name = "Quy trình OT test",
+                ApplicableType = ApprovalWorkflowApplicableType.OtRequest,
+                IsActive = true,
+                IsUserSelectable = true,
+            };
+            var step = new ApprovalWorkflowStep
+            {
+                Id = Guid.NewGuid(),
+                ApprovalWorkflowId = wf.Id,
+                Order = 1,
+                DepartmentId = null,
+                Name = "Bước 1",
+            };
+            var lvl = new ApprovalWorkflowLevel
+            {
+                Id = Guid.NewGuid(),
+                ApprovalWorkflowStepId = step.Id,
+                Order = 1,
+                ApproverUserId = approver.Id,
+            };
+            db.ApprovalWorkflows.Add(wf);
+            db.ApprovalWorkflowSteps.Add(step);
+            db.ApprovalWorkflowLevels.Add(lvl);
+
+            var ot = new OtRequest
+            {
+                Id = Guid.NewGuid(),
+                RequesterUserId = requester.Id,
+                RequesterFullName = "Người tạo",
+                OtDate = FixedNow.Date,
+                StartTime = TimeSpan.FromHours(18),
+                EndTime = TimeSpan.FromHours(21),
+                Hours = 3,
+                Reason = "Tăng ca giao hàng",
+                Status = WorkflowAppStatus.Nhap,
+                ApprovalWorkflowId = wf.Id,
+            };
+            db.OtRequests.Add(ot);
+            await db.SaveChangesAsync(CancellationToken.None);
+
+            await new SubmitOtRequestHandler(db, AsUser(requester), clock)
+                .Handle(new SubmitOtRequestCommand(ot.Id), CancellationToken.None);
+            ot.Status.Should().Be(WorkflowAppStatus.DaGuiDuyet);
+            ot.CurrentApprovalLevelOrder.Should().Be(1);
+            ot.MaDonTu.Should().Be("DT/OT/2026/001");
+
+            await new ApproveOtRequestHandler(db, AsUser(approver), clock)
+                .Handle(new ApproveOtRequestCommand(ot.Id, null), CancellationToken.None);
+            ot.Status.Should().Be(WorkflowAppStatus.DaDuyet);
+            ot.CurrentApprovalLevelOrder.Should().BeNull();
+
+            var opinions = await db.OtRequestLevelOpinions.Where(o => o.OtRequestId == ot.Id).ToListAsync();
+            opinions.Should().HaveCount(1);
+            opinions[0].Comment.Should().Be("(duyệt — không ý kiến)");
+        }
+    }
+}