[CLAUDE] App: Plan B Chunk E2 — ContractDetailDto +ApprovalWorkflowId + LevelOpinions[] populate

Mirror PE PeDetailBundle pattern. Expose V2 workflow state cho FE Section 5
Chunk E3 (Implementer pending) render dynamic LevelOpinionsSectionV2.

Changes:
- ContractDtos.cs:
  - ContractDetailDto +3 fields (default null backward compat):
    - Guid? ApprovalWorkflowId (V2 pin)
    - int? CurrentApprovalLevelOrder
    - List<ContractLevelOpinionDto>? LevelOpinions
  - NEW record ContractLevelOpinionDto (mirror PE 12 fields)
- ContractFeatures.cs GetContractQueryHandler:
  - Load LevelOpinions via 3-step JOIN (ContractLevelOpinions + ApprovalWorkflowLevels.Include(Step) + Users)
  - Map to ContractLevelOpinionDto với StepOrder/Name + LevelOrder/Name + Approver/SignedBy resolve
  - OrderBy StepOrder + LevelOrder
  - Null fallback Comment "" (CS8604 silence)
  - Empty list khi V2 pin nhưng KHÔNG có opinion (workflow start lúc Drafter trình)
  - Skip load nếu V1 (ApprovalWorkflowId null) → null marker FE detect

FE Chunk E3 sẽ:
- Detect V2 mode qua `bundle.approvalWorkflowId != null`
- Fetch ApprovalFlow shape via existing /api/approval-workflows-v2/{ApprovalWorkflowId}
- Render Section 5 dynamic forEach Step → forEach Level → 1 OpinionBox với opinion data from LevelOpinions[]

Verify:
- dotnet build PASS 0 err, 0 warn (clean)
- dotnet test 111/111 PASS — 0 regression
- V1 legacy contract Detail unchanged (ApprovalWorkflowId=null + LevelOpinions=null)

Plan B chain status (8/9 chunks done):
- A1 58898e8 ✅ Entity
- A2 a85e437 ✅ Mig 32 + Seed
- B 138469d ✅ Service ApproveV2 branch
- C 26c98d3 ✅ Mig 33 LevelOpinions
- B2 1f199b0 ✅ UPSERT block
- E1 ef23308 ✅ CreateContractCommand +V2
- D 62b50d1 ✅ FE Workspace V2
- E2 (this) ✅ ContractDetailDto +V2 + LevelOpinions populate
- E3 FE Section 5 LevelOpinionsV2 (Implementer next)

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

src/Backend/SolutionErp.Application/Contracts/ContractFeatures.cs

@@ -477,6 +477,54 @@ public class GetContractQueryHandler(
             workflowPolicy = WorkflowPolicyRegistry.ForContractWithOverrides(c, workflowOverrides);
         }
 
+        // [Plan B S29 2026-05-22 Chunk E2] Load V2 LevelOpinions nếu pin ApprovalWorkflowId.
+        // JOIN ApprovalWorkflowLevel + Step + Approver User để build dynamic DTO
+        // cho FE Section 5 render dynamic theo flow shape. V1 legacy → empty list.
+        List<ContractLevelOpinionDto>? levelOpinionsDto = null;
+        if (c.ApprovalWorkflowId is Guid awIdLoad)
+        {
+            var opinions = await db.ContractLevelOpinions.AsNoTracking()
+                .Where(o => o.ContractId == c.Id)
+                .ToListAsync(ct);
+            if (opinions.Count > 0)
+            {
+                var levelIds = opinions.Select(o => o.ApprovalWorkflowLevelId).ToHashSet();
+                var levels = await db.ApprovalWorkflowLevels.AsNoTracking()
+                    .Include(l => l.Step)
+                    .Where(l => levelIds.Contains(l.Id))
+                    .ToListAsync(ct);
+                var approverUserIds = levels.Select(l => l.ApproverUserId).ToHashSet();
+                var approverNames = await userManager.Users.AsNoTracking()
+                    .Where(u => approverUserIds.Contains(u.Id))
+                    .ToDictionaryAsync(u => u.Id, u => u.FullName, ct);
+                levelOpinionsDto = opinions
+                    .Select(o =>
+                    {
+                        var level = levels.FirstOrDefault(l => l.Id == o.ApprovalWorkflowLevelId);
+                        var step = level?.Step;
+                        return new ContractLevelOpinionDto(
+                            o.Id,
+                            o.ApprovalWorkflowLevelId,
+                            StepOrder: step?.Order ?? 0,
+                            StepName: step?.Name ?? "",
+                            LevelOrder: level?.Order ?? 0,
+                            LevelName: level?.Name,
+                            ApproverUserId: level?.ApproverUserId ?? Guid.Empty,
+                            ApproverFullName: level != null && approverNames.TryGetValue(level.ApproverUserId, out var afn) ? afn : null,
+                            o.Comment ?? "",
+                            o.SignedAt,
+                            o.SignedByUserId,
+                            o.SignedByFullName);
+                    })
+                    .OrderBy(d => d.StepOrder).ThenBy(d => d.LevelOrder)
+                    .ToList();
+            }
+            else
+            {
+                levelOpinionsDto = new List<ContractLevelOpinionDto>();
+            }
+        }
+
         // Resolve user names
         var userIds = new HashSet<Guid>();
         if (c.DrafterUserId is Guid did) userIds.Add(did);
@@ -516,7 +564,11 @@ public class GetContractQueryHandler(
                     att.Id, att.FileName, att.StoragePath, att.FileSize,
                     att.ContentType, att.Purpose, att.Note, att.CreatedAt))
                 .ToList(),
-            BuildWorkflowSummary(c, workflowPolicy));
+            BuildWorkflowSummary(c, workflowPolicy),
+            // [Plan B S29 2026-05-22 Chunk E2] V2 fields
+            ApprovalWorkflowId: c.ApprovalWorkflowId,
+            CurrentApprovalLevelOrder: c.CurrentApprovalLevelOrder,
+            LevelOpinions: levelOpinionsDto);
     }
 
     // FE uses this to render next-phase buttons dynamically — no more hardcoded

src/Backend/SolutionErp.Application/Contracts/Dtos/ContractDtos.cs

@@ -46,7 +46,34 @@ public record ContractDetailDto(
     List<ContractApprovalDto> Approvals,
     List<ContractCommentDto> Comments,
     List<ContractAttachmentDto> Attachments,
-    WorkflowSummaryDto Workflow);
+    WorkflowSummaryDto Workflow,
+    // [Plan B S29 2026-05-22 Chunk E2] V2 workflow fields — mirror PE pattern.
+    // ApprovalWorkflowId pin lúc create (Mig 32). FE Section 5 detect V2 mode
+    // qua field này: nếu Guid → render dynamic LevelOpinionsSectionV2;
+    // nếu null → V1 legacy KHÔNG Section 5 V2.
+    // FE fetch ApprovalFlow shape via /api/approval-workflows-v2/{ApprovalWorkflowId}.
+    Guid? ApprovalWorkflowId = null,
+    int? CurrentApprovalLevelOrder = null,
+    List<ContractLevelOpinionDto>? LevelOpinions = null);
+
+// [Plan B S29 2026-05-22 Chunk E2] Ý kiến cấp duyệt V2 dynamic theo
+// ApprovalWorkflowLevel. Mirror PE PurchaseEvaluationLevelOpinionDto pattern.
+// Service ApproveV2Async UPSERT (Plan B Chunk B2 1f199b0). Comment empty
+// fallback "(duyệt — không ý kiến)". SignedByUserId !== Level.ApproverUserId
+// → FE show banner "Admin duyệt thay".
+public record ContractLevelOpinionDto(
+    Guid Id,
+    Guid ApprovalWorkflowLevelId,
+    int StepOrder,
+    string StepName,
+    int LevelOrder,
+    string? LevelName,
+    Guid ApproverUserId,
+    string? ApproverFullName,
+    string Comment,
+    DateTime SignedAt,
+    Guid SignedByUserId,
+    string? SignedByFullName);
 
 // Policy snapshot for the FE — lets UI render next-phase buttons dynamically
 // without hardcoding the transition map (single source of truth in BE).