[CLAUDE] Supplier: Excel-import Phase B (upload NCC preview/confirm) + Mig 63

Import Excel 'Database NCC': upload→preview classify (New/Update/Skip/Error)→confirm all-or-nothing upsert-by-Code (OrdinalIgnoreCase dedup, fill-nulls-safe). Mig 63 +SourceUpdatedAt/By (2 nullable). Parser layout-locked header-fingerprint NFC-normalized + absolute-cell-index + #REF!-null + NAS-backslash-raw. Type-lạ→NhaCungCap. FE dialog fe-admin+fe-user byte-identical. 10 test SupplierExcelImportServiceTests.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/Backend/SolutionErp.Infrastructure/Persistence/Configurations/SupplierConfiguration.cs

@@ -41,6 +41,9 @@ public class SupplierConfiguration : IEntityTypeConfiguration<Supplier>
         b.Property(x => x.OwnerPmh).HasMaxLength(150);
         b.Property(x => x.Status).HasConversion<int>();   // nullable int enum
 
+        // Import provenance (Supplier Phase B). SourceUpdatedAt = DateTime? (no length). SourceUpdatedBy = text.
+        b.Property(x => x.SourceUpdatedBy).HasMaxLength(200);
+
         b.HasIndex(x => x.Code).IsUnique().HasFilter("[IsDeleted] = 0");   // Mig 47 (gotcha #57 EXT) — soft-deleted slot reusable, khớp HasQueryFilter !IsDeleted app-check
         b.HasIndex(x => x.Type);
 

src/Backend/SolutionErp.Infrastructure/Persistence/Migrations/20260712070117_AddSupplierImportSourceFields.cs

@@ -0,0 +1,40 @@
+using System;
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace SolutionErp.Infrastructure.Persistence.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddSupplierImportSourceFields : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<DateTime>(
+                name: "SourceUpdatedAt",
+                table: "Suppliers",
+                type: "datetime2",
+                nullable: true);
+
+            migrationBuilder.AddColumn<string>(
+                name: "SourceUpdatedBy",
+                table: "Suppliers",
+                type: "nvarchar(200)",
+                maxLength: 200,
+                nullable: true);
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropColumn(
+                name: "SourceUpdatedAt",
+                table: "Suppliers");
+
+            migrationBuilder.DropColumn(
+                name: "SourceUpdatedBy",
+                table: "Suppliers");
+        }
+    }
+}

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

@@ -3327,6 +3327,13 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
                         .HasMaxLength(500)
                         .HasColumnType("nvarchar(500)");
 
+                    b.Property<DateTime?>("SourceUpdatedAt")
+                        .HasColumnType("datetime2");
+
+                    b.Property<string>("SourceUpdatedBy")
+                        .HasMaxLength(200)
+                        .HasColumnType("nvarchar(200)");
+
                     b.Property<int?>("Status")
                         .HasColumnType("int");