fix: attempt to terminate process gracefully

Author: hwaxxer

src/mcp/client/stdio.py

@@ -159,4 +159,7 @@ async def stdin_writer():
     ):
         tg.start_soon(stdout_reader)
         tg.start_soon(stdin_writer)
-        yield read_stream, write_stream
+        try:
+            yield read_stream, write_stream
+        finally:
+            process.terminate()