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/tcp_helpers.py

@@ -0,0 +1,37 @@
+"""Helper methods to tune a TCP connection"""
+
+import asyncio
+import socket
+from contextlib import suppress
+from typing import Optional  # noqa
+
+__all__ = ("tcp_keepalive", "tcp_nodelay")
+
+
+if hasattr(socket, "SO_KEEPALIVE"):
+
+    def tcp_keepalive(transport: asyncio.Transport) -> None:
+        sock = transport.get_extra_info("socket")
+        if sock is not None:
+            sock.setsockopt(socket.SOL_SOCKET, socket.SO_KEEPALIVE, 1)
+
+else:
+
+    def tcp_keepalive(transport: asyncio.Transport) -> None:  # pragma: no cover
+        pass
+
+
+def tcp_nodelay(transport: asyncio.Transport, value: bool) -> None:
+    sock = transport.get_extra_info("socket")
+
+    if sock is None:
+        return
+
+    if sock.family not in (socket.AF_INET, socket.AF_INET6):
+        return
+
+    value = bool(value)
+
+    # socket may be closed already, on windows OSError get raised
+    with suppress(OSError):
+        sock.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, value)