fix(agents): ShellToolMiddleware session lost on HIL resume

Author: aroun-coumar

libs/langchain_v1/langchain/agents/middleware/shell_tool.py

@@ -677,8 +677,10 @@ def _run_shell_tool(
         if payload.get("restart"):
             LOGGER.info("Restarting shell session on request.")
             try:
-                session.restart()
+                session.stop(self._execution_policy.termination_timeout)
+                session.start()
                 self._run_startup_commands(session)
+                self._session = session
             except BaseException as err:
                 LOGGER.exception("Restarting shell session failed; session remains unavailable.")
                 msg = "Failed to restart shell session."