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/websockets/legacy/exceptions.py

@@ -0,0 +1,71 @@
+import http
+
+from .. import datastructures
+from ..exceptions import (
+    InvalidHandshake,
+    # InvalidMessage was incorrectly moved here in versions 14.0 and 14.1.
+    InvalidMessage,  # noqa: F401
+    ProtocolError as WebSocketProtocolError,  # noqa: F401
+)
+from ..typing import StatusLike
+
+
+class InvalidStatusCode(InvalidHandshake):
+    """
+    Raised when a handshake response status code is invalid.
+
+    """
+
+    def __init__(self, status_code: int, headers: datastructures.Headers) -> None:
+        self.status_code = status_code
+        self.headers = headers
+
+    def __str__(self) -> str:
+        return f"server rejected WebSocket connection: HTTP {self.status_code}"
+
+
+class AbortHandshake(InvalidHandshake):
+    """
+    Raised to abort the handshake on purpose and return an HTTP response.
+
+    This exception is an implementation detail.
+
+    The public API is
+    :meth:`~websockets.legacy.server.WebSocketServerProtocol.process_request`.
+
+    Attributes:
+        status (~http.HTTPStatus): HTTP status code.
+        headers (Headers): HTTP response headers.
+        body (bytes): HTTP response body.
+    """
+
+    def __init__(
+        self,
+        status: StatusLike,
+        headers: datastructures.HeadersLike,
+        body: bytes = b"",
+    ) -> None:
+        # If a user passes an int instead of an HTTPStatus, fix it automatically.
+        self.status = http.HTTPStatus(status)
+        self.headers = datastructures.Headers(headers)
+        self.body = body
+
+    def __str__(self) -> str:
+        return (
+            f"HTTP {self.status:d}, {len(self.headers)} headers, {len(self.body)} bytes"
+        )
+
+
+class RedirectHandshake(InvalidHandshake):
+    """
+    Raised when a handshake gets redirected.
+
+    This exception is an implementation detail.
+
+    """
+
+    def __init__(self, uri: str) -> None:
+        self.uri = uri
+
+    def __str__(self) -> str:
+        return f"redirect to {self.uri}"