fix: 修复 ruff import 排序告警和 Django 镜像源 403 问题

- backend/app/core/background_init.py: 惰性导入按名称排序
- backend/app/router/note_router.py: first-party 导入块按字母序排列
- backend/app/services/note_service.py: 惰性导入顺序修正
- DjangoUserService/pyproject.toml: 默认索引改为 pypi.org，tuna 降为备用镜像

Author: RMA-MUN

DjangoUserService/pyproject.toml

@@ -34,11 +34,10 @@ include = ["DjangoUserService", "apps"]
 
 [[tool.uv.index]]
 url = "https://pypi.tuna.tsinghua.edu.cn/simple"
-default = true
 
 [build-system]
 requires = ["setuptools", "wheel"]
 build-backend = "setuptools.build_meta"
 
 [tool.uv]
-index-url = "https://pypi.tuna.tsinghua.edu.cn/simple"
+index-url = "https://pypi.org/simple"

backend/app/core/background_init.py

@@ -91,7 +91,7 @@ async def _init_note_service(self):
 
     async def _init_reranker(self):
         """检查并初始化重排序模型（触发 torch 等重型框架加载）"""
-        from app.rag.reorder_service import check_and_download_reranker_model, ReorderService
+        from app.rag.reorder_service import ReorderService, check_and_download_reranker_model
 
         await asyncio.to_thread(check_and_download_reranker_model)
         logger.info("✅ 重排序模型检查完成")

backend/app/router/note_router.py

@@ -8,6 +8,7 @@
 from pydantic import BaseModel
 from sqlalchemy.ext.asyncio import AsyncSession
 
+from app.core.background_init import init_manager
 from app.core.rate_limit import rate_limit
 from app.core.success_response import success_response
 from app.db.db_config import get_db
@@ -16,7 +17,6 @@
     NoteListResponse,
     NoteUpdate,
 )
-from app.core.background_init import init_manager
 from app.utils.auth_utils import get_current_user_id
 
 note_router = APIRouter(prefix="/note", tags=["note"])

backend/app/services/note_service.py

@@ -375,8 +375,8 @@ async def _auto_tag_and_review(self, note_id: str, user_id: str, content: str):
             prompt = prompt_template.replace("{content}", content)
 
             # 惰性导入避免模块级循环依赖
-            from app.db.db_config import AsyncSessionLocal
             from app.core.background_init import init_manager
+            from app.db.db_config import AsyncSessionLocal
             chat_model = init_manager.chat_model
 
             response = await chat_model.ainvoke([HumanMessage(content=prompt)])