chore: 添加虚拟环境到仓库

- 添加 backend_service/venv 虚拟环境
- 包含所有Python依赖包
- 注意：虚拟环境约393MB，包含12655个文件

backend_service/venv/lib/python3.13/site-packages/attr/_cmp.pyi

@@ -0,0 +1,13 @@
+from typing import Any, Callable
+
+_CompareWithType = Callable[[Any, Any], bool]
+
+def cmp_using(
+    eq: _CompareWithType | None = ...,
+    lt: _CompareWithType | None = ...,
+    le: _CompareWithType | None = ...,
+    gt: _CompareWithType | None = ...,
+    ge: _CompareWithType | None = ...,
+    require_same_type: bool = ...,
+    class_name: str = ...,
+) -> type: ...