fix: 菜单固定为全局

src/Application/TakeoutSaaS.Application/Identity/Handlers/UpdateMenuCommandHandler.cs

@@ -1,4 +1,5 @@
 using MediatR;
+using TakeoutSaaS.Application.Identity;
 using TakeoutSaaS.Application.Identity.Commands;
 using TakeoutSaaS.Application.Identity.Contracts;
 using TakeoutSaaS.Domain.Identity.Repositories;
@@ -19,12 +20,18 @@ public sealed class UpdateMenuCommandHandler(
     /// <inheritdoc />
     public async Task<MenuDefinitionDto?> Handle(UpdateMenuCommand request, CancellationToken cancellationToken)
     {
-        // 1. 校验存在
+        // 1. 菜单固定时禁止修改
+        if (!MenuPolicy.CanMaintainMenus)
+        {
+            throw new BusinessException(ErrorCodes.Forbidden, "菜单已固定，禁止修改");
+        }
+
+        // 2. 校验存在
         var tenantId = tenantProvider.GetCurrentTenantId();
         var entity = await menuRepository.FindByIdAsync(request.Id, tenantId, cancellationToken)
             ?? throw new BusinessException(ErrorCodes.NotFound, "菜单不存在");
 
-        // 2. 更新字段
+        // 3. 更新字段
         entity.ParentId = request.ParentId;
         entity.Name = request.Name.Trim();
         entity.Path = request.Path.Trim();
@@ -42,11 +49,11 @@ public sealed class UpdateMenuCommandHandler(
             ? null
             : System.Text.Json.JsonSerializer.Serialize(request.AuthList);
 
-        // 3. 持久化
+        // 4. 持久化
         await menuRepository.UpdateAsync(entity, cancellationToken);
         await menuRepository.SaveChangesAsync(cancellationToken);
 
-        // 4. 返回 DTO
+        // 5. 返回 DTO
         return MenuMapper.ToDto(entity);
     }
 }