When stopping gunicorn with Ctrl+C, the gevent worker's handle_quit()
calls sys.exit(0) inside a greenlet, causing gevent to print a
SystemExit traceback. Add a gunicorn config with post_worker_init hook
that marks SystemExit as a non-error in gevent's hub.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
