fix: 修复后端代码违规并更新协议文档

- 修复 notifications 模块 datetime.now() 缺少时区问题
- 用 ApiProblemError 替换 BaseService 中的 HTTPException
- 更新协议文档：添加错误码、繁体字段、邀请相关协议
- 升级 Docker 镜像版本

backend/src/core/db/base_service.py

@@ -2,9 +2,8 @@ from __future__ import annotations
 
 from uuid import UUID
 
-from fastapi import HTTPException
-
 from core.auth.models import CurrentUser
+from core.http.errors import ApiProblemError, problem_payload
 
 
 class BaseService:
@@ -15,7 +14,10 @@ class BaseService:
 
     def require_current_user(self) -> CurrentUser:
         if self._current_user is None:
-            raise HTTPException(status_code=401, detail="Unauthorized")
+            raise ApiProblemError(
+                status_code=401,
+                detail=problem_payload(code="AUTH_UNAUTHORIZED", detail="Unauthorized"),
+            )
         return self._current_user
 
     def require_user_id(self) -> UUID: