Ensure that the update thread is stopped even after an error.

vigil

@@ -998,11 +998,13 @@ def main(root_path, worker_count=None, is_sandboxed=True, editor_command=None,
             with _urwid_screen() as urwid_screen:
                 loop.add_reader(sys.stdin, on_input, urwid_screen)
                 update_display_thread.start()
+                try:
                     signal.signal(signal.SIGWINCH, on_window_resize)
                     with contextlib.suppress(KeyboardInterrupt):
                         loop.run_forever()
                     log.log_command("Exiting...")
                     time.sleep(0.05)
+                finally:
                     _UPDATE_THREAD_STOPPED = True
                     appearance_changed_event.set()
                     update_display_thread.join()