[CLAUDE] FE-Admin+Docs: Contract workflow N-stage Designer mirror PE + Docs (Chunk F)

FE Admin WorkflowsPage Designer extend mirror PeWorkflowsPage:
- Type InnerStepDto + extend StepDto +innerSteps
- Type EditInnerStep + extend EditStep +innerSteps
- copyFromDefinition include innerSteps map
- Default new step +innerSteps:[]
- departmentsList useQuery
- Save mutation payload include innerSteps Order asc
- UI sub-section "Cấp duyệt nhỏ trong phòng" drag-list per step card với
  Phòng × Cấp + required checkbox + button "+ Thêm cấp duyệt" emerald
- Empty state hint fallback 2-cấp legacy

KHÔNG đụng fe-user — WorkflowsPage admin-only.

Reuse PositionLevel const + Label maps từ Session 12 types/users.ts.

Docs:
- STATUS.md Last updated + Phase summary (19→20 mig, 89→95 test, 56→57
  bảng) + 1 row Recently Done Session 13 (KEEP narrative cũ)
- HANDOFF.md TL;DR Session 13 prepend + 7 cảnh báo Session 14+
- migration-todos.md Phase 9 + Session 13 block 5 chunk
- Session log NEW `2026-05-07-2400-n-stage-contract-mirror.md` đầy đủ
  rationale + per-chunk + bug log

Defer cron audit 2026-06-01: schema-diagram §17 Mig 20, skill
ef-core-migration row, skill contract-workflow N-stage cross-ref.

🎉 SESSION 13 COMPLETE: Mirror N-stage Contract module (Mig 20). 5
commit per-chunk + skip Chunk E auto-bind. Total 95 test pass.
Backward compat 100% với 2-stage Mig 16 legacy.

Pending Task 4: Wire BE TraLai PE transition + Task 2: Sample data seed.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

docs/HANDOFF.md

@@ -1,6 +1,50 @@
 # HANDOFF — Brief 5 phút cho session tiếp theo
 
-**Last updated:** 2026-05-07 (Session 12 — **N-stage workflow approval Phòng × PositionLevel cấu hình động — Mig 18+19. 6 commit per-chunk: Domain → App CQRS → Service logic → Tests +6 → API → FE Designer + UsersPage. 89 test pass. PE-only first.**)
+**Last updated:** 2026-05-07 (Session 13 — **Mirror N-stage Contract (Mig 20, 5 commit per-chunk + skip Chunk E auto-bind). Domain → App → Service → Tests +6 → FE Designer. 95 test pass. Budget defer cần versioned WF.**)
+
+## TL;DR Session 13 (07/05 — Mirror N-stage workflow sang Contract)
+
+User chỉ thị mirror N-stage từ PE (Mig 18+19) sang Contract. Budget defer (cần migration `AddBudgetVersionedWorkflow` trước — hardcoded `BudgetPolicy.Default` chưa có WorkflowDefinition entity).
+
+**5 chunk per-commit** (Chunk E skipped — WorkflowsController auto-bind record qua [FromBody]):
+
+- **Chunk A (`951ffa3`)** Domain `WorkflowStepInnerStep` + nav WorkflowStep.InnerSteps + ALTER ContractDeptApproval.InnerStepId + EF config + **Migration 20** GỘP 1 (CREATE TABLE + ALTER + DropIndex old + Recreate filtered legacy/N-stage)
+- **Chunk B (`04cf2a0`)** Application CQRS DTO/Input/Validator/Handler mirror PE Chunk B (default null backward compat)
+- **Chunk C (`e247b67`)** ContractWorkflowService refactor — load InnerSteps eager + reject clear N-stage rows + dept block split hasInnerSteps→N-stage / else→legacy 2-stage
+- **Chunk D (`7c0772a`)** ContractNStageApprovalTests 6 test mirror PE + helper SeedWorkflowDefinitionAsync 2 step adjacent + FakeChangelogService + FakeContractCodeGenerator stubs. **89→95 test pass**
+- **Chunk E SKIP** — auto-bind no code change
+- **Chunk F (current)** FE WorkflowsPage Designer extend InnerSteps sub-section mirror PeWorkflowsPage + Docs
+
+**Verify:** dotnet build pass + dotnet ef database update Mig 20 LocalDB applied + dotnet test 95 pass + npm build fe-admin pass.
+
+**Cumulative sau Session 13:**
+
+| | Trước S13 | Sau S13 |
+|---|---:|---:|
+| BE LOC | ~15300 | ~15700 (+400) |
+| Migrations | 19 | **20** (+Mig 20) |
+| DB tables | 56 | **57** (+1 WorkflowStepInnerSteps) |
+| DB columns mới | — | +1 (ContractDeptApproval.InnerStepId) |
+| API endpoints | ~134 | ~134 (no change — auto-bind) |
+| FE pages | 32 | 32 (extend existing WorkflowsPage) |
+| Tests | 89 | **95** (+6 Contract N-stage) |
+| Commits | (after S12) | **+5** (A→F per-chunk, E skipped) |
+
+## ⚠️ CẢNH BÁO Session 14+
+
+1. **Budget N-stage defer** — Budget chưa có versioned WorkflowDefinition entity (hardcoded `BudgetPolicy.Default`). Để mirror N-stage Budget cần migration `AddBudgetVersionedWorkflow` trước (4 bảng `BudgetWorkflowDefinitions/Steps/StepApprovers/InnerSteps` + `Budget.WorkflowDefinitionId?`). Defer cho user quyết riêng — feature mở rộng module Budget lớn.
+
+2. **PE-only deploy first** — Contract N-stage giờ đã có nhưng PE đã được test trước. UAT cả 2 module song song để verify pattern reusable.
+
+3. **Sample data N-stage** — pending (Task 2). Khi user yêu cầu sẽ seed PositionLevel cho 30 demo user + 1 N-stage workflow definition active cho DuyetNcc + 1 cho ContractType (ví dụ HopDongThauPhu).
+
+4. **TraLai BE wire** — pending (Task 4). Phase TraLai = 98 enum đã có ở Session S11+++++++ FE side, nhưng BE workflow service chưa wire button "Trả lại" cho approver. Khi user yêu cầu sẽ thêm decision `SendBack` (or reuse Reject với target=TraLai) + Service logic + FE button trong Workflow Panel.
+
+5. **schema-diagram §17 Mig 20** chưa update — defer cron audit 2026-06-01.
+
+6. **Skill ef-core-migration Mig 20 row** chưa add — defer cron audit.
+
+7. **Skill contract-workflow N-stage cross-ref** chưa add — defer cron audit.
 
 ## TL;DR Session 12 (07/05 — N-stage workflow approval per phase × dept × cấp)