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/rich/_extension.py

@@ -0,0 +1,10 @@
+from typing import Any
+
+
+def load_ipython_extension(ip: Any) -> None:  # pragma: no cover
+    # prevent circular import
+    from rich.pretty import install
+    from rich.traceback import install as tr_install
+
+    install()
+    tr_install()