feat: 实现动态租户解析与移除菜单回退逻辑

1. 新增 ITenantCodeResolver 接口和 DatabaseTenantCodeResolver 实现
2. 修改 TenantResolutionMiddleware 支持从数据库动态解析租户编码
3. ITenantRepository 新增 FindIdByCodeAsync 方法
4. 移除 EfMenuRepository 中危险的系统菜单回退逻辑
5. 调整服务注册顺序确保依赖正确注入

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/Api/TakeoutSaaS.TenantApi/Program.cs

@@ -85,8 +85,7 @@ if (isDevelopment)
     });
 }
 
-// 5. 注册多租户解析、鉴权授权与权限策略
-builder.Services.AddTenantResolution(builder.Configuration);
+// 5. 注册鉴权授权与权限策略
 builder.Services.AddJwtAuthentication(builder.Configuration);
 builder.Services.AddAuthorization();
 builder.Services.AddPermissionAuthorization();
@@ -98,6 +97,9 @@ builder.Services.AddIdentityApplication(enableMiniSupport: false);
 builder.Services.AddAppInfrastructure(builder.Configuration);
 builder.Services.AddIdentityInfrastructure(builder.Configuration, enableMiniFeatures: false, enableAdminSeed: false);
 
+// 7. 注册多租户解析（依赖 ITenantRepository，需在 Infrastructure 之后）
+builder.Services.AddTenantResolution(builder.Configuration);
+
 // 6. (空行后) 注册字典模块（系统参数、字典项、缓存等）
 builder.Services.AddDictionaryApplication();
 builder.Services.AddDictionaryInfrastructure(builder.Configuration);

src/Api/TakeoutSaaS.TenantApi/appsettings.Development.json

@@ -56,7 +56,9 @@
       "/health",
       "/healthz"
     ],
-    "RootDomain": ""
+    "RootDomain": "laosankeji.com",
+    "CodeTenantMap": {},
+    "ThrowIfUnresolved": false
   },
   "Cors": {
     "Tenant": []