feat: profile 返回当前套餐名称

在认证档案中增加 packageName 字段，并基于租户当前有效订阅从套餐表读取名称返回给前端，便于头像下拉直接展示真实套餐信息。

src/Api/TakeoutSaaS.TenantApi/Controllers/AuthController.cs

@@ -68,6 +68,7 @@ public sealed class AuthController(IAdminAuthService authService) : BaseApiContr
     ///     "account": "admin",
     ///     "displayName": "租户管理员",
     ///     "tenantId": "100000000000000001",
+    ///     "packageName": "标准版",
     ///     "roles": ["tenant-admin"],
     ///     "permissions": ["identity:profile:read", "merchant:read"]
     ///   }