[CLAUDE] Infra: Plan B Chunk A2 — Mig 32 Contract V2 schema + Configuration + Seed sample workflow

Cookie-cutter mirror PE Mig 23+24 GỘP thành 1 Mig 32 (ADD 2 column +
FK + IX). Mirror Mig 26 pattern cho FK Restrict.

Files added/modified:
- Migrations/20260522051059_AddApprovalWorkflowToContract.cs (3-file rule ✅)
- Migrations/20260522051059_AddApprovalWorkflowToContract.Designer.cs
- Migrations/ApplicationDbContextModelSnapshot.cs (updated)
- Configurations/ContractConfiguration.cs (+HasIndex + FK Restrict ApprovalWorkflows)
- Persistence/DbInitializer.cs (SeedSampleContractWorkflowV2 idempotent QT-HD-V2-001)

Mig 32 Up():
- ADD COLUMN Contracts.ApprovalWorkflowId Guid? NULL
- ADD COLUMN Contracts.CurrentApprovalLevelOrder int? NULL
- ADD INDEX IX_Contracts_ApprovalWorkflowId (filtered NOT NULL)
- ADD FK FK_Contracts_ApprovalWorkflows_ApprovalWorkflowId Restrict

Seed sample workflow (UAT smoke + admin Designer default):
- Code: QT-HD-V2-001 Name: "Quy trình duyệt HĐ mẫu UAT V2"
- ApplicableType: 3 (Contract) IsActive: true IsUserSelectable: true
- 1 Step "Bước 1 - Phòng CCM" + 1 Level + Approver Lê Văn Bình CCM
- Idempotent: skip nếu Code+Version existing

V1 coexist: 7 prod contract giữ WorkflowDefinitionId; V2 mới pin
ApprovalWorkflowId. Service ApproveV2Async (Chunk B em main) sẽ branch.

Verify (Implementer):
- dotnet build SolutionErp.slnx PASS 0 err (em main WIP stashed for verify)
- dotnet ef database update Dev PASS (Mig 32 applied)
- 3-file rule Mig: mig.cs + Designer.cs + Snapshot.cs

Plan B chain (6 chunks):
- A1 58898e8 Contract +2 fields (em main, done)
- A2 (this) Mig 32 schema + Config + Seed (Implementer Case 2, done)
- B Service ApproveV2Async branch (em main, in progress)
- C Mig 33 ContractLevelOpinions (Implementer, pending)
- D FE Workspace V2 (Implementer, pending)
- E FE Section 5 V2 (Implementer, pending)

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

src/Backend/SolutionErp.Infrastructure/Persistence/Migrations/20260522051059_AddApprovalWorkflowToContract.cs

@@ -0,0 +1,60 @@
+using System;
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace SolutionErp.Infrastructure.Persistence.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddApprovalWorkflowToContract : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<Guid>(
+                name: "ApprovalWorkflowId",
+                table: "Contracts",
+                type: "uniqueidentifier",
+                nullable: true);
+
+            migrationBuilder.AddColumn<int>(
+                name: "CurrentApprovalLevelOrder",
+                table: "Contracts",
+                type: "int",
+                nullable: true);
+
+            migrationBuilder.CreateIndex(
+                name: "IX_Contracts_ApprovalWorkflowId",
+                table: "Contracts",
+                column: "ApprovalWorkflowId");
+
+            migrationBuilder.AddForeignKey(
+                name: "FK_Contracts_ApprovalWorkflows_ApprovalWorkflowId",
+                table: "Contracts",
+                column: "ApprovalWorkflowId",
+                principalTable: "ApprovalWorkflows",
+                principalColumn: "Id",
+                onDelete: ReferentialAction.Restrict);
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropForeignKey(
+                name: "FK_Contracts_ApprovalWorkflows_ApprovalWorkflowId",
+                table: "Contracts");
+
+            migrationBuilder.DropIndex(
+                name: "IX_Contracts_ApprovalWorkflowId",
+                table: "Contracts");
+
+            migrationBuilder.DropColumn(
+                name: "ApprovalWorkflowId",
+                table: "Contracts");
+
+            migrationBuilder.DropColumn(
+                name: "CurrentApprovalLevelOrder",
+                table: "Contracts");
+        }
+    }
+}

src/Backend/SolutionErp.Infrastructure/Persistence/Migrations/ApplicationDbContextModelSnapshot.cs

@@ -637,6 +637,9 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
                         .ValueGeneratedOnAdd()
                         .HasColumnType("uniqueidentifier");
 
+                    b.Property<Guid?>("ApprovalWorkflowId")
+                        .HasColumnType("uniqueidentifier");
+
                     b.Property<Guid?>("BudgetId")
                         .HasColumnType("uniqueidentifier");
 
@@ -657,6 +660,9 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
                     b.Property<Guid?>("CreatedBy")
                         .HasColumnType("uniqueidentifier");
 
+                    b.Property<int?>("CurrentApprovalLevelOrder")
+                        .HasColumnType("int");
+
                     b.Property<int?>("CurrentWorkflowStepIndex")
                         .HasColumnType("int");
 
@@ -732,6 +738,8 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
 
                     b.HasKey("Id");
 
+                    b.HasIndex("ApprovalWorkflowId");
+
                     b.HasIndex("BudgetId");
 
                     b.HasIndex("MaHopDong")
@@ -3479,6 +3487,14 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
                     b.Navigation("Budget");
                 });
 
+            modelBuilder.Entity("SolutionErp.Domain.Contracts.Contract", b =>
+                {
+                    b.HasOne("SolutionErp.Domain.ApprovalWorkflowsV2.ApprovalWorkflow", null)
+                        .WithMany()
+                        .HasForeignKey("ApprovalWorkflowId")
+                        .OnDelete(DeleteBehavior.Restrict);
+                });
+
             modelBuilder.Entity("SolutionErp.Domain.Contracts.ContractApproval", b =>
                 {
                     b.HasOne("SolutionErp.Domain.Contracts.Contract", "Contract")