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/aiohttp/http_websocket.py

@@ -0,0 +1,36 @@
+"""WebSocket protocol versions 13 and 8."""
+
+from ._websocket.helpers import WS_KEY, ws_ext_gen, ws_ext_parse
+from ._websocket.models import (
+    WS_CLOSED_MESSAGE,
+    WS_CLOSING_MESSAGE,
+    WebSocketError,
+    WSCloseCode,
+    WSHandshakeError,
+    WSMessage,
+    WSMsgType,
+)
+from ._websocket.reader import WebSocketReader
+from ._websocket.writer import WebSocketWriter
+
+# Messages that the WebSocketResponse.receive needs to handle internally
+_INTERNAL_RECEIVE_TYPES = frozenset(
+    (WSMsgType.CLOSE, WSMsgType.CLOSING, WSMsgType.PING, WSMsgType.PONG)
+)
+
+
+__all__ = (
+    "WS_CLOSED_MESSAGE",
+    "WS_CLOSING_MESSAGE",
+    "WS_KEY",
+    "WebSocketReader",
+    "WebSocketWriter",
+    "WSMessage",
+    "WebSocketError",
+    "WSMsgType",
+    "WSCloseCode",
+    "ws_ext_gen",
+    "ws_ext_parse",
+    "WSHandshakeError",
+    "WSMessage",
+)