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

docs/protocols/auth/session-auth-protocol.md

@@ -36,6 +36,11 @@ Gateway error codes from `backend/src/v1/auth/gateway.py`:
 - `AUTH_VERIFICATION_CODE_INVALID`
 - `AUTH_REFRESH_TOKEN_INVALID`
 - `AUTH_REFRESH_TOKEN_MISSING`
+- `AUTH_USER_NOT_FOUND`
+
+Authorization error codes from `backend/src/v1/users/dependencies.py`:
+
+- `AUTH_UNAUTHORIZED`
 
 ## Frontend route mapping