[CLAUDE] Workflow: State machine 5 trạng thái — Trả lại = Phase riêng

Session 17 spec: chốt 5 trạng thái phiếu PE/HĐ/Budget theo state diagram:
  Nháp ─trình──► Đã gửi duyệt ─approve cấp cuối──► Đã duyệt (terminal)
                              ├─ Trả lại ────────► Trả lại
                              └─ Từ chối ────────► Từ chối (terminal)
  Trả lại ──Drafter sửa+gửi lại──► Đã gửi duyệt (chạy LẠI từ đầu)

Khác Mig 21 (Session 16): bỏ smart-reject jump-back. Trả lại = Phase
RIÊNG (TraLai=98), không revert về DangSoanThao + không jump-back step.
Drafter từ TraLai gửi lại như case Nháp — workflow chạy lại từ Cấp 1
Bước 1 (Option A diagram chốt với user).

BE Domain:
- ContractPhase + TraLai = 98
- BudgetPhase + TraLai = 98
- PurchaseEvaluationPhase: TraLai=98 đổi từ [LEGACY deprecated] thành
  primary state. Comment update enum docs cho cả 3.

BE Policy (PE/HĐ/Budget):
- Reject transitions trỏ về TraLai (thay DangSoanThao)
- Mirror entry transitions: TraLai → next phase (cho Drafter resubmit)
- ActivePhases thêm TraLai
- FromDefinition mirror: TraLai → step.Phase + reject → TraLai
- DefaultSla cho TraLai = same as DangSoanThao

BE Service (PE + Contract):
- Reject branch: target=TuChoi giữ; else set Phase=TraLai, clear
  CurrentWorkflowStepIndex=null
- Bỏ ResumeAfterReject branch + RejectedAtStepIndex/RejectedFromPhase
  assignment (DB column giữ deprecated cho data cũ)
- Drafter trình branch: từ DangSoanThao HOẶC TraLai → ChoDuyet, init
  CurrentWorkflowStepIndex=0 (cùng entry point, chạy lại từ đầu)
- Notification: TraLai when fromPhase=ChoDuyet → "bị trả lại"
- Budget Handler: simplify reject → TraLai, bỏ smart-reject + isResuming

BE Tests update:
- WorkflowPolicyTests: Standard_RejectFromCCM → TraLai (rename + assert)
  + Standard_TraLai_To_DangGopY_Allowed_For_Drafter (new)
- PurchaseEvaluationPolicyTests: BothPolicies_RejectFromCCM → TraLai
  + BothPolicies_TraLai_To_ChoPurchasing_AllowedForDrafter (new theory)
- BudgetPolicyTests: Default_CostControl_ChoCCM_To_TraLai (rename)
  + ActivePhases All6States (was All5) + NextPhasesFrom_TraLai (new)
  + NextPhasesFrom_ChoCEO_Includes_DaDuyet_And_TraLai (rename)
- 77 → 81 test pass (+4 tests TraLai entry point)

FE rename "Bản nháp" → "Nháp" (cả 2 app + types):
- types/purchaseEvaluation.ts: PurchaseEvaluationPhaseLabel 1=Nháp,
  10=Đã gửi duyệt. PeDisplayStatus.BanNhap → Nhap (key + value).
  PhaseLabel/Color cho TraLai update active.
- types/contracts.ts: +ChoDuyet=10, +TraLai=98 const + label/color.
  Phase 2 'Đang soạn thảo' → 'Nháp'.
- types/budget.ts: +TraLai=98 const + label/color. Phase 1 → 'Nháp'.
- PeListPanel + PurchaseEvaluationsListPage filter dropdown: Nhap +
  TraLai map đúng phase value.

BE label maps update consistent:
- ContractExcelExporter PhaseLabel: DangSoanThao → "Nháp" + add ChoDuyet/
  TraLai entries.
- PeWorkflowAdminFeatures + WorkflowAdminFeatures PhaseLabels: same.

Verify: dotnet test 81 pass · npm build × 2 app pass · BE 0 error.

Field RejectedAtStepIndex/RejectedFromPhase giữ DB column (nullable,
không set value mới). Cleanup migration sau.

src/Backend/SolutionErp.Domain/Contracts/ContractPhase.cs

@@ -1,25 +1,28 @@
 namespace SolutionErp.Domain.Contracts;
 
-// State machine HĐ — Session 16 drastic refactor (Mig 21):
-//   DangSoanThao → ChoDuyet (Drafter trình, init CurrentWorkflowStepIndex=0)
-//   ChoDuyet → ChoDuyet (advance step pointer per approve)
-//   ChoDuyet → DaPhatHanh (last step done — terminal)
-//   ChoDuyet → DangSoanThao (Trả lại — save RejectedAtStepIndex, Drafter sửa)
-//   ChoDuyet → TuChoi (Từ chối — terminal khoá)
+// State machine HĐ — Session 17 spec mới (5 trạng thái):
+//   DangSoanThao (Nháp)        ──Drafter trình──► ChoDuyet
+//   TraLai       (Trả lại)     ──Drafter sửa+gửi lại──► ChoDuyet (chạy lại từ Cấp 1 Bước 1)
+//   ChoDuyet     (Đã gửi duyệt) ──advance step pointer──► ChoDuyet
+//                              ──last step done──────────► DaPhatHanh (terminal + gen mã HĐ)
+//                              ──Approver Trả lại────────► TraLai
+//                              ──Approver Từ chối────────► TuChoi (terminal)
 //
 // LEGACY values (DangChon, DangGopY, DangDamPhan, DangInKy, DangKiemTraCCM,
 // DangTrinhKy, DangDongDau) deprecated post-Mig 21 — giữ enum cho data cũ.
+// TraLai=98: Session 17 thêm mới — Trả lại là Phase RIÊNG (mirror PE).
 public enum ContractPhase
 {
     DangChon = 1,              // [LEGACY]
-    DangSoanThao = 2,
+    DangSoanThao = 2,          // Nháp
     DangGopY = 3,              // [LEGACY]
     DangDamPhan = 4,           // [LEGACY]
     DangInKy = 5,              // [LEGACY]
     DangKiemTraCCM = 6,        // [LEGACY]
     DangTrinhKy = 7,           // [LEGACY]
     DangDongDau = 8,           // [LEGACY]
-    DaPhatHanh = 9,            // terminal thành công (= DaDuyet cho HĐ)
-    ChoDuyet = 10,             // [Mig 21] generic intermediate, dùng CurrentWorkflowStepIndex tracking
-    TuChoi = 99,               // terminal khoá
+    DaPhatHanh = 9,            // Đã duyệt (cho HĐ — gen mã + phát hành) — terminal thành công
+    ChoDuyet = 10,             // Đã gửi duyệt — generic intermediate, CurrentWorkflowStepIndex tracking
+    TraLai = 98,               // Trả lại — Phase riêng, Drafter sửa rồi gửi lại chạy từ đầu
+    TuChoi = 99,               // Từ chối — terminal khoá
 }

src/Backend/SolutionErp.Domain/Contracts/WorkflowPolicy.cs

@@ -52,6 +52,7 @@ public static class WorkflowPolicies
     private static readonly Dictionary<ContractPhase, TimeSpan?> DefaultSla = new()
     {
         [ContractPhase.DangSoanThao] = TimeSpan.FromDays(7),
+        [ContractPhase.TraLai] = TimeSpan.FromDays(7),
         [ContractPhase.DangGopY] = TimeSpan.FromDays(7),
         [ContractPhase.DangDamPhan] = TimeSpan.FromDays(7),
         [ContractPhase.DangInKy] = TimeSpan.FromDays(1),
@@ -65,6 +66,8 @@ public static class WorkflowPolicies
 
     // ===== STANDARD: 9-phase formal workflow =====
     // Per QT-TP-NCC.docx: Thầu phụ / NCC / Tổ đội — full CCM review required.
+    // Session 17: Reject = về TraLai (Phase riêng). Drafter từ TraLai gửi lại
+    // = entry point thứ 2 (mirror DangSoanThao → DangGopY).
     public static readonly WorkflowPolicy Standard = new(
         Name: "Standard",
         Description: "Quy trình đầy đủ 8 phase — CCM kiểm tra + BOD duyệt. Áp dụng HĐ Thầu phụ / NCC / Giao khoán.",
@@ -72,26 +75,28 @@ public static class WorkflowPolicies
         {
             [(ContractPhase.DangSoanThao, ContractPhase.DangGopY)] = [AppRoles.Drafter, AppRoles.DeptManager],
             [(ContractPhase.DangSoanThao, ContractPhase.TuChoi)] = [AppRoles.Drafter, AppRoles.DeptManager],
+            [(ContractPhase.TraLai, ContractPhase.DangGopY)] = [AppRoles.Drafter, AppRoles.DeptManager],
+            [(ContractPhase.TraLai, ContractPhase.TuChoi)] = [AppRoles.Drafter, AppRoles.DeptManager],
 
             [(ContractPhase.DangGopY, ContractPhase.DangDamPhan)] = [AppRoles.Drafter, AppRoles.DeptManager],
-            [(ContractPhase.DangGopY, ContractPhase.DangSoanThao)] = [AppRoles.ProjectManager, AppRoles.Procurement, AppRoles.CostControl, AppRoles.Finance, AppRoles.Accounting, AppRoles.Equipment],
+            [(ContractPhase.DangGopY, ContractPhase.TraLai)] = [AppRoles.ProjectManager, AppRoles.Procurement, AppRoles.CostControl, AppRoles.Finance, AppRoles.Accounting, AppRoles.Equipment],
 
             [(ContractPhase.DangDamPhan, ContractPhase.DangInKy)] = [AppRoles.Drafter, AppRoles.DeptManager, AppRoles.ProjectManager],
 
             [(ContractPhase.DangInKy, ContractPhase.DangKiemTraCCM)] = [AppRoles.Drafter, AppRoles.DeptManager, AppRoles.ProjectManager],
 
             [(ContractPhase.DangKiemTraCCM, ContractPhase.DangTrinhKy)] = [AppRoles.CostControl],
-            [(ContractPhase.DangKiemTraCCM, ContractPhase.DangSoanThao)] = [AppRoles.CostControl],
+            [(ContractPhase.DangKiemTraCCM, ContractPhase.TraLai)] = [AppRoles.CostControl],
 
             [(ContractPhase.DangTrinhKy, ContractPhase.DangDongDau)] = [AppRoles.Director, AppRoles.AuthorizedSigner],
-            [(ContractPhase.DangTrinhKy, ContractPhase.DangSoanThao)] = [AppRoles.Director, AppRoles.AuthorizedSigner],
+            [(ContractPhase.DangTrinhKy, ContractPhase.TraLai)] = [AppRoles.Director, AppRoles.AuthorizedSigner],
 
             [(ContractPhase.DangDongDau, ContractPhase.DaPhatHanh)] = [AppRoles.HrAdmin],
         },
         PhaseSla: DefaultSla,
         ActivePhases:
         [
-            ContractPhase.DangSoanThao, ContractPhase.DangGopY, ContractPhase.DangDamPhan,
+            ContractPhase.DangSoanThao, ContractPhase.TraLai, ContractPhase.DangGopY, ContractPhase.DangDamPhan,
             ContractPhase.DangInKy, ContractPhase.DangKiemTraCCM, ContractPhase.DangTrinhKy,
             ContractPhase.DangDongDau, ContractPhase.DaPhatHanh, ContractPhase.TuChoi,
         ]);
@@ -106,9 +111,11 @@ public static class WorkflowPolicies
         {
             [(ContractPhase.DangSoanThao, ContractPhase.DangGopY)] = [AppRoles.Drafter, AppRoles.DeptManager],
             [(ContractPhase.DangSoanThao, ContractPhase.TuChoi)] = [AppRoles.Drafter, AppRoles.DeptManager],
+            [(ContractPhase.TraLai, ContractPhase.DangGopY)] = [AppRoles.Drafter, AppRoles.DeptManager],
+            [(ContractPhase.TraLai, ContractPhase.TuChoi)] = [AppRoles.Drafter, AppRoles.DeptManager],
 
             [(ContractPhase.DangGopY, ContractPhase.DangDamPhan)] = [AppRoles.Drafter, AppRoles.DeptManager],
-            [(ContractPhase.DangGopY, ContractPhase.DangSoanThao)] = [AppRoles.ProjectManager, AppRoles.Procurement, AppRoles.CostControl, AppRoles.Finance, AppRoles.Accounting, AppRoles.Equipment],
+            [(ContractPhase.DangGopY, ContractPhase.TraLai)] = [AppRoles.ProjectManager, AppRoles.Procurement, AppRoles.CostControl, AppRoles.Finance, AppRoles.Accounting, AppRoles.Equipment],
 
             [(ContractPhase.DangDamPhan, ContractPhase.DangInKy)] = [AppRoles.Drafter, AppRoles.DeptManager, AppRoles.ProjectManager],
 
@@ -116,14 +123,14 @@ public static class WorkflowPolicies
             [(ContractPhase.DangInKy, ContractPhase.DangTrinhKy)] = [AppRoles.Drafter, AppRoles.DeptManager, AppRoles.ProjectManager],
 
             [(ContractPhase.DangTrinhKy, ContractPhase.DangDongDau)] = [AppRoles.Director, AppRoles.AuthorizedSigner],
-            [(ContractPhase.DangTrinhKy, ContractPhase.DangSoanThao)] = [AppRoles.Director, AppRoles.AuthorizedSigner],
+            [(ContractPhase.DangTrinhKy, ContractPhase.TraLai)] = [AppRoles.Director, AppRoles.AuthorizedSigner],
 
             [(ContractPhase.DangDongDau, ContractPhase.DaPhatHanh)] = [AppRoles.HrAdmin],
         },
         PhaseSla: DefaultSla,
         ActivePhases:
         [
-            ContractPhase.DangSoanThao, ContractPhase.DangGopY, ContractPhase.DangDamPhan,
+            ContractPhase.DangSoanThao, ContractPhase.TraLai, ContractPhase.DangGopY, ContractPhase.DangDamPhan,
             ContractPhase.DangInKy, ContractPhase.DangTrinhKy,
             ContractPhase.DangDongDau, ContractPhase.DaPhatHanh, ContractPhase.TuChoi,
         ]);
@@ -213,22 +220,35 @@ public static class WorkflowPolicyRegistry
                 transitions[(prev.Value, s.Phase)] = roles;
                 if (userIds.Length > 0) userTransitions[(prev.Value, s.Phase)] = userIds;
 
-                // Reject path back to Drafter (common pattern QT docx)
+                // Mirror: TraLai → s.Phase (Drafter resubmit từ Trả lại = entry point thứ 2)
+                if (prev.Value == ContractPhase.DangSoanThao)
+                {
+                    transitions.TryAdd((ContractPhase.TraLai, s.Phase), roles);
+                    if (userIds.Length > 0)
+                        userTransitions.TryAdd((ContractPhase.TraLai, s.Phase), userIds);
+                }
+
+                // Reject path → TraLai (Phase riêng, không revert DangSoanThao)
                 if (prev.Value != ContractPhase.DangSoanThao && s.Phase != ContractPhase.DangSoanThao)
                 {
-                    transitions.TryAdd((s.Phase, ContractPhase.DangSoanThao), roles);
+                    transitions.TryAdd((s.Phase, ContractPhase.TraLai), roles);
                     if (userIds.Length > 0)
-                        userTransitions.TryAdd((s.Phase, ContractPhase.DangSoanThao), userIds);
+                        userTransitions.TryAdd((s.Phase, ContractPhase.TraLai), userIds);
                 }
             }
             prev = s.Phase;
         }
-        // First step có thể reject to TuChoi
+        // First step có thể reject to TuChoi (cả Nháp + Trả lại)
         if (steps.Count > 0)
+        {
             transitions.TryAdd((steps[0].Phase, ContractPhase.TuChoi),
                 [AppRoles.Drafter, AppRoles.DeptManager]);
+            transitions.TryAdd((ContractPhase.TraLai, ContractPhase.TuChoi),
+                [AppRoles.Drafter, AppRoles.DeptManager]);
+        }
 
         if (!activePhases.Contains(ContractPhase.TuChoi)) activePhases.Add(ContractPhase.TuChoi);
+        if (!activePhases.Contains(ContractPhase.TraLai)) activePhases.Add(ContractPhase.TraLai);
 
         return new WorkflowPolicy(
             Name: $"{def.Code}-v{def.Version:D2}",