fix: 修复商户中心查询 RowVersion 列不存在问题

src/Application/TakeoutSaaS.Application/App/Merchants/Commands/UpdateMerchantCommand.cs

@@ -44,7 +44,7 @@ public sealed record UpdateMerchantCommand : IRequest<UpdateMerchantResultDto?>
     public string? ContactEmail { get; init; }
 
     /// <summary>
-    /// 并发控制版本。
+    /// 并发控制版本（兼容字段，当前由数据库 xmin 托管）。
     /// </summary>
-    public byte[] RowVersion { get; init; } = Array.Empty<byte>();
+    public byte[]? RowVersion { get; init; }
 }

src/Application/TakeoutSaaS.Application/App/Merchants/Handlers/UpdateMerchantCommandHandler.cs

@@ -29,16 +29,11 @@ public sealed class UpdateMerchantCommandHandler(
     /// <inheritdoc />
     public async Task<UpdateMerchantResultDto?> Handle(UpdateMerchantCommand request, CancellationToken cancellationToken)
     {
-        if (request.RowVersion == null || request.RowVersion.Length == 0)
-        {
-            throw new BusinessException(ErrorCodes.ValidationFailed, "RowVersion 不能为空");
-        }
-
         // 1. 获取操作者权限
         var currentTenantId = tenantProvider.GetCurrentTenantId();
 
         // 2. 读取商户信息
-        var merchant = await merchantRepository.FindByIdAsync(request.MerchantId, currentTenantId, cancellationToken);
+        var merchant = await merchantRepository.GetForUpdateAsync(request.MerchantId, currentTenantId, cancellationToken);
 
         if (merchant == null)
         {
@@ -73,7 +68,6 @@ public sealed class UpdateMerchantCommandHandler(
         merchant.Address = registeredAddress;
         merchant.ContactPhone = contactPhone;
         merchant.ContactEmail = contactEmail;
-        merchant.RowVersion = request.RowVersion;
 
         var requiresReview = merchant.Status == MerchantStatus.Approved && criticalChanged;
         if (requiresReview)

src/Application/TakeoutSaaS.Application/App/Merchants/Validators/UpdateMerchantCommandValidator.cs

@@ -21,6 +21,5 @@ public sealed class UpdateMerchantCommandValidator : AbstractValidator<UpdateMer
         RuleFor(x => x.ContactPhone).NotEmpty().MaximumLength(32);
         RuleFor(x => x.ContactEmail).EmailAddress().MaximumLength(128)
             .When(x => !string.IsNullOrWhiteSpace(x.ContactEmail));
-        RuleFor(x => x.RowVersion).NotEmpty();
     }
 }

src/Domain/TakeoutSaaS.Domain/Merchants/Repositories/IMerchantRepository.cs

@@ -18,6 +18,15 @@ public interface IMerchantRepository
     /// <returns>商户实体或 null。</returns>
     Task<Merchant?> FindByIdAsync(long merchantId, long tenantId, CancellationToken cancellationToken = default);
 
+    /// <summary>
+    /// 依据标识获取商户（用于更新，返回可跟踪实体）。
+    /// </summary>
+    /// <param name="merchantId">商户 ID。</param>
+    /// <param name="tenantId">租户 ID。</param>
+    /// <param name="cancellationToken">取消标记。</param>
+    /// <returns>商户实体或 null。</returns>
+    Task<Merchant?> GetForUpdateAsync(long merchantId, long tenantId, CancellationToken cancellationToken = default);
+
     /// <summary>
     /// 按状态筛选商户列表。
     /// </summary>

src/Infrastructure/TakeoutSaaS.Infrastructure/App/Persistence/TakeoutAppDbContext.cs

@@ -536,10 +536,12 @@ public sealed class TakeoutAppDbContext(
         builder.Property(x => x.IsFrozen).HasDefaultValue(false);
         builder.Property(x => x.FrozenReason).HasMaxLength(500);
         builder.Property(x => x.ClaimedByName).HasMaxLength(100);
-        builder.Property(x => x.RowVersion)
-            .IsRowVersion()
-            .IsConcurrencyToken()
-            .HasColumnType("bytea");
+        builder.Ignore(x => x.RowVersion);
+        builder.Property<uint>("xmin")
+            .HasColumnName("xmin")
+            .HasColumnType("xid")
+            .ValueGeneratedOnAddOrUpdate()
+            .IsConcurrencyToken();
         builder.HasIndex(x => x.TenantId);
         builder.HasIndex(x => new { x.TenantId, x.Status });
         builder.HasIndex(x => x.ClaimedBy);

src/Infrastructure/TakeoutSaaS.Infrastructure/App/Repositories/EfMerchantRepository.cs

@@ -25,6 +25,14 @@ public sealed class EfMerchantRepository(TakeoutAppDbContext context, TakeoutLog
             .FirstOrDefaultAsync(cancellationToken);
     }
 
+    /// <inheritdoc />
+    public Task<Merchant?> GetForUpdateAsync(long merchantId, long tenantId, CancellationToken cancellationToken = default)
+    {
+        return context.Merchants
+            .Where(x => x.TenantId == tenantId && x.Id == merchantId)
+            .FirstOrDefaultAsync(cancellationToken);
+    }
+
     /// <inheritdoc />
     public async Task<IReadOnlyList<Merchant>> SearchAsync(long tenantId, MerchantStatus? status, CancellationToken cancellationToken = default)
     {