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/mcp/shared/context.py

@@ -0,0 +1,20 @@
+from dataclasses import dataclass
+from typing import Any, Generic
+
+from typing_extensions import TypeVar
+
+from mcp.shared.session import BaseSession
+from mcp.types import RequestId, RequestParams
+
+SessionT = TypeVar("SessionT", bound=BaseSession[Any, Any, Any, Any, Any])
+LifespanContextT = TypeVar("LifespanContextT")
+RequestT = TypeVar("RequestT", default=Any)
+
+
+@dataclass
+class RequestContext(Generic[SessionT, LifespanContextT, RequestT]):
+    request_id: RequestId
+    meta: RequestParams.Meta | None
+    session: SessionT
+    lifespan_context: LifespanContextT
+    request: RequestT | None = None