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/os/posix/__init__.py

@@ -0,0 +1 @@
+"""POSIX-specific utilities for MCP."""

backend_service/venv/lib/python3.13/site-packages/mcp/os/posix/utilities.py

@@ -0,0 +1,60 @@
+"""
+POSIX-specific functionality for stdio client operations.
+"""
+
+import logging
+import os
+import signal
+
+import anyio
+from anyio.abc import Process
+
+logger = logging.getLogger(__name__)
+
+
+async def terminate_posix_process_tree(process: Process, timeout_seconds: float = 2.0) -> None:
+    """
+    Terminate a process and all its children on POSIX systems.
+
+    Uses os.killpg() for atomic process group termination.
+
+    Args:
+        process: The process to terminate
+        timeout_seconds: Timeout in seconds before force killing (default: 2.0)
+    """
+    pid = getattr(process, "pid", None) or getattr(getattr(process, "popen", None), "pid", None)
+    if not pid:
+        # No PID means there's no process to terminate - it either never started,
+        # already exited, or we have an invalid process object
+        return
+
+    try:
+        pgid = os.getpgid(pid)
+        os.killpg(pgid, signal.SIGTERM)
+
+        with anyio.move_on_after(timeout_seconds):
+            while True:
+                try:
+                    # Check if process group still exists (signal 0 = check only)
+                    os.killpg(pgid, 0)
+                    await anyio.sleep(0.1)
+                except ProcessLookupError:
+                    return
+
+        try:
+            os.killpg(pgid, signal.SIGKILL)
+        except ProcessLookupError:
+            pass
+
+    except (ProcessLookupError, PermissionError, OSError) as e:
+        logger.warning(f"Process group termination failed for PID {pid}: {e}, falling back to simple terminate")
+        try:
+            process.terminate()
+            with anyio.fail_after(timeout_seconds):
+                await process.wait()
+        except Exception:
+            logger.warning(f"Process termination failed for PID {pid}, attempting force kill")
+            try:
+                process.kill()
+            except Exception:
+                logger.exception(f"Failed to kill process {pid}")