[CLAUDE] Infra+App: Chunk C — Smart reject + Resume after reject (3 module)

Ràng buộc 2 (Phase 9): khi reject, trả về Drafter (DangSoanThao) + lưu phase
nguồn. Drafter sửa lại + trình lại → quay về phase đã reject (skip phase
trung gian).

Logic flow:

1. Reject (Decision=Reject):
   - entity.RejectedFromPhase = currentPhase  // snapshot phase đang reject
   - targetPhase override = DangSoanThao       // force về Drafter
   - Approval row: FromPhase=X, ToPhase=DangSoanThao, Decision=Reject
   - Notification cho Drafter

2. Resume after reject (Decision=Approve, fromPhase=DangSoanThao,
   RejectedFromPhase != null):
   - targetPhase override = entity.RejectedFromPhase!.Value
   - entity.RejectedFromPhase = null  // clear field
   - Skip policy guard (Drafter có quyền trình lại sau khi sửa)
   - Approval row: FromPhase=DangSoanThao, ToPhase=ResumePhase, Decision=Approve

3. Normal transition (chưa reject hoặc đã clear):
   - Logic cũ giữ nguyên — policy guard check + transition

Pattern unified cho 3 module:
- ContractWorkflowService.TransitionAsync: 2 case detect + override
- PurchaseEvaluationWorkflowService.TransitionAsync: tương tự
- TransitionBudgetCommandHandler.Handle: tương tự (Budget không có service riêng,
  logic ở handler)

Files:
- src/Backend/SolutionErp.Infrastructure/Services/ContractWorkflowService.cs
- src/Backend/SolutionErp.Infrastructure/Services/PurchaseEvaluationWorkflowService.cs
- src/Backend/SolutionErp.Application/Budgets/BudgetFeatures.cs

Verify:
- Build pass (2 warning DocxRenderer cũ, không liên quan)
- 77 unit test pass — Domain policy không đổi, tests giữ nguyên

Note: Approval history giờ track đầy đủ cycle reject→sửa→resume:
  Approval 1: DangGopY → DangSoanThao, Decision=Reject (CCM reject)
  Approval 2: DangSoanThao → DangGopY, Decision=Approve (Drafter resume)

UI có thể detect "đã từng reject" qua RejectedFromPhase != null hoặc
qua Approval history (Decision=Reject row gần nhất). Hiển thị banner
đỏ "Phiếu đã bị reject từ phase X, lý do: Y" cho Drafter.

Smart reject hoàn tất Ràng buộc 2. Còn Ràng buộc 3 (2-stage dept approval)
ở Chunk D.

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

src/Backend/SolutionErp.Application/Budgets/BudgetFeatures.cs

@@ -131,24 +131,43 @@ public class TransitionBudgetCommandHandler(
         var entity = await db.Budgets.FirstOrDefaultAsync(x => x.Id == request.Id, ct)
             ?? throw new NotFoundException("Budget", request.Id);
 
+        // ===== Smart reject + resume (Phase 9 — Migration 16) =====
+        var fromPhase = entity.Phase;
+        var targetPhase = request.TargetPhase;
+        var isResumingAfterReject = request.Decision == ApprovalDecision.Approve
+            && fromPhase == BudgetPhase.DangSoanThao
+            && entity.RejectedFromPhase != null;
+
+        if (request.Decision == ApprovalDecision.Reject)
+        {
+            entity.RejectedFromPhase = fromPhase;
+            targetPhase = BudgetPhase.DangSoanThao;
+        }
+        else if (isResumingAfterReject)
+        {
+            targetPhase = entity.RejectedFromPhase!.Value;
+            entity.RejectedFromPhase = null;
+        }
+
         var policy = BudgetPolicies.Default;
         var isAdmin = currentUser.Roles.Contains(AppRoles.Admin);
 
-        if (!isAdmin && !policy.IsTransitionAllowed(entity.Phase, request.TargetPhase, currentUser.Roles))
+        // Policy guard — bypass khi resume sau reject.
+        if (!isAdmin && !isResumingAfterReject
+            && !policy.IsTransitionAllowed(fromPhase, targetPhase, currentUser.Roles))
             throw new ForbiddenException(
-                $"Role không đủ quyền chuyển {entity.Phase} → {request.TargetPhase}.");
+                $"Role không đủ quyền chuyển {fromPhase} → {targetPhase}.");
 
-        var fromPhase = entity.Phase;
         entity.SlaWarningSent = false;
-        entity.Phase = request.TargetPhase;
-        var sla = policy.PhaseSla.GetValueOrDefault(request.TargetPhase);
+        entity.Phase = targetPhase;
+        var sla = policy.PhaseSla.GetValueOrDefault(targetPhase);
         entity.SlaDeadline = sla is null ? null : DateTime.UtcNow.Add(sla.Value);
 
         db.BudgetApprovals.Add(new BudgetApproval
         {
             BudgetId = entity.Id,
             FromPhase = fromPhase,
-            ToPhase = request.TargetPhase,
+            ToPhase = targetPhase,
             ApproverUserId = currentUser.UserId,
             Decision = request.Decision,
             Comment = request.Comment,
@@ -166,10 +185,10 @@ public class TransitionBudgetCommandHandler(
             BudgetId = entity.Id,
             EntityType = BudgetEntityType.Workflow,
             Action = ChangelogAction.Transition,
-            PhaseAtChange = request.TargetPhase,
+            PhaseAtChange = targetPhase,
             UserId = currentUser.UserId,
             UserName = actorName ?? "Hệ thống",
-            Summary = $"Chuyển phase {fromPhase} → {request.TargetPhase}",
+            Summary = $"Chuyển phase {fromPhase} → {targetPhase}",
             ContextNote = request.Comment,
         });
         await db.SaveChangesAsync(ct);

src/Backend/SolutionErp.Infrastructure/Services/ContractWorkflowService.cs

@@ -37,6 +37,26 @@ public class ContractWorkflowService(
         if (contract.Phase == targetPhase)
             throw new ConflictException("HĐ đã ở phase đích.");
 
+        // ===== Smart reject + resume (Phase 9 — Migration 16) =====
+        // Reject: override target = DangSoanThao + lưu phase gốc → Drafter sửa.
+        // Resume sau reject: Drafter trình từ DangSoanThao + RejectedFromPhase
+        // != null → jump straight tới phase đã reject, bypass phase trung gian.
+        var fromPhase = contract.Phase;
+        var isResumingAfterReject = decision == ApprovalDecision.Approve
+            && fromPhase == ContractPhase.DangSoanThao
+            && contract.RejectedFromPhase != null;
+
+        if (decision == ApprovalDecision.Reject)
+        {
+            contract.RejectedFromPhase = fromPhase;
+            targetPhase = ContractPhase.DangSoanThao;
+        }
+        else if (isResumingAfterReject)
+        {
+            targetPhase = contract.RejectedFromPhase!.Value;
+            contract.RejectedFromPhase = null;
+        }
+
         // Resolve the workflow: prefer the pinned WorkflowDefinition (new
         // versioned system), else fall back to the static/override registry
         // (legacy path for contracts created before versioning rolled out).
@@ -60,31 +80,31 @@ public class ContractWorkflowService(
         var isAdmin = actorRoles.Contains(AppRoles.Admin);
         var isSystem = actorUserId is null && decision == ApprovalDecision.AutoApprove;
 
-        if (!isAdmin && !isSystem)
+        // Policy guard — bypass cho resume (Drafter có quyền trình lại sau khi
+        // sửa, không cần policy check vì target đã pinned bởi RejectedFromPhase).
+        if (!isAdmin && !isSystem && !isResumingAfterReject)
         {
-            if (!policy.Transitions.TryGetValue((contract.Phase, targetPhase), out var allowedRoles))
+            if (!policy.Transitions.TryGetValue((fromPhase, targetPhase), out var allowedRoles))
                 throw new ForbiddenException(
-                    $"Policy '{policy.Name}' không cho phép {contract.Phase} → {targetPhase}. " +
+                    $"Policy '{policy.Name}' không cho phép {fromPhase} → {targetPhase}. " +
                     $"Kiểm tra ContractType hoặc BypassProcurementAndCCM.");
 
             // Sử dụng IsTransitionAllowed — check Role + User-kind fallback.
             // User-kind chỉ áp dụng khi WorkflowDefinition pinned có
             // WorkflowStepApprover Kind=User cho step này.
-            if (!policy.IsTransitionAllowed(contract.Phase, targetPhase, actorRoles, actorUserId))
+            if (!policy.IsTransitionAllowed(fromPhase, targetPhase, actorRoles, actorUserId))
             {
                 var userExtra = policy.UserTransitions is not null
-                    && policy.UserTransitions.TryGetValue((contract.Phase, targetPhase), out var userIds)
+                    && policy.UserTransitions.TryGetValue((fromPhase, targetPhase), out var userIds)
                     && userIds.Length > 0
                     ? $" hoặc {userIds.Length} user explicit"
                     : "";
                 throw new ForbiddenException(
-                    $"Role ({string.Join(",", actorRoles)}) không đủ quyền chuyển {contract.Phase} → {targetPhase}. " +
+                    $"Role ({string.Join(",", actorRoles)}) không đủ quyền chuyển {fromPhase} → {targetPhase}. " +
                     $"Policy '{policy.Name}' yêu cầu: {string.Join(",", allowedRoles)}{userExtra}.");
             }
         }
 
-        var fromPhase = contract.Phase;
-
         // Defensive — gen mã HĐ nếu chưa có khi chuyển sang DangDongDau.
         // Nominal flow (sau user feedback): mã đã gen sẵn từ CreateContract → skip.
         // Fallback chỉ trigger cho HĐ legacy chưa qua backfill, hoặc HĐ tạo bằng

src/Backend/SolutionErp.Infrastructure/Services/PurchaseEvaluationWorkflowService.cs

@@ -34,6 +34,23 @@ public class PurchaseEvaluationWorkflowService(
         if (evaluation.Phase == targetPhase)
             throw new ConflictException("Phiếu đã ở phase đích.");
 
+        // ===== Smart reject + resume (Phase 9 — Migration 16) =====
+        var fromPhase = evaluation.Phase;
+        var isResumingAfterReject = decision == ApprovalDecision.Approve
+            && fromPhase == PurchaseEvaluationPhase.DangSoanThao
+            && evaluation.RejectedFromPhase != null;
+
+        if (decision == ApprovalDecision.Reject)
+        {
+            evaluation.RejectedFromPhase = fromPhase;
+            targetPhase = PurchaseEvaluationPhase.DangSoanThao;
+        }
+        else if (isResumingAfterReject)
+        {
+            targetPhase = evaluation.RejectedFromPhase!.Value;
+            evaluation.RejectedFromPhase = null;
+        }
+
         PurchaseEvaluationPolicy policy;
         if (evaluation.WorkflowDefinitionId is Guid wfId)
         {
@@ -53,21 +70,21 @@ public class PurchaseEvaluationWorkflowService(
         var isAdmin = actorRoles.Contains(AppRoles.Admin);
         var isSystem = actorUserId is null && decision == ApprovalDecision.AutoApprove;
 
-        if (!isAdmin && !isSystem)
+        // Policy guard — bypass khi resume sau reject (target đã pinned).
+        if (!isAdmin && !isSystem && !isResumingAfterReject)
         {
-            if (!policy.Transitions.TryGetValue((evaluation.Phase, targetPhase), out var allowedRoles))
+            if (!policy.Transitions.TryGetValue((fromPhase, targetPhase), out var allowedRoles))
                 throw new ForbiddenException(
-                    $"Policy '{policy.Name}' không cho phép {evaluation.Phase} → {targetPhase}.");
+                    $"Policy '{policy.Name}' không cho phép {fromPhase} → {targetPhase}.");
 
-            if (!policy.IsTransitionAllowed(evaluation.Phase, targetPhase, actorRoles, actorUserId))
+            if (!policy.IsTransitionAllowed(fromPhase, targetPhase, actorRoles, actorUserId))
             {
                 throw new ForbiddenException(
-                    $"Role ({string.Join(",", actorRoles)}) không đủ quyền chuyển {evaluation.Phase} → {targetPhase}. " +
+                    $"Role ({string.Join(",", actorRoles)}) không đủ quyền chuyển {fromPhase} → {targetPhase}. " +
                     $"Policy '{policy.Name}' yêu cầu: {string.Join(",", allowedRoles)}.");
             }
         }
 
-        var fromPhase = evaluation.Phase;
         evaluation.SlaWarningSent = false;
         evaluation.Phase = targetPhase;