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/socketio/base_namespace.py

@@ -0,0 +1,33 @@
+class BaseNamespace:
+    def __init__(self, namespace=None):
+        self.namespace = namespace or '/'
+
+    def is_asyncio_based(self):
+        return False
+
+
+class BaseServerNamespace(BaseNamespace):
+    def __init__(self, namespace=None):
+        super().__init__(namespace=namespace)
+        self.server = None
+
+    def _set_server(self, server):
+        self.server = server
+
+    def rooms(self, sid, namespace=None):
+        """Return the rooms a client is in.
+
+        The only difference with the :func:`socketio.Server.rooms` method is
+        that when the ``namespace`` argument is not given the namespace
+        associated with the class is used.
+        """
+        return self.server.rooms(sid, namespace=namespace or self.namespace)
+
+
+class BaseClientNamespace(BaseNamespace):
+    def __init__(self, namespace=None):
+        super().__init__(namespace=namespace)
+        self.client = None
+
+    def _set_client(self, client):
+        self.client = client