cmd_update's auto-restart path could leave the gateway dead after a
transient failure in systemd's own auto-restart window. Reproduced
on Ubuntu 25.10 + systemd 257: after update, gateway drains and exits 75,
systemd's first respawn 60s later fails (status=200/CHDIR with
"No such file or directory" on a WorkingDirectory that demonstrably
exists), the unit ends up in RestartMaxDelaySec=300 backoff, and
cmd_update's fallback 'systemctl restart' never recovers it — leaving
users with a permanently silent gateway until they manually run
'systemctl reset-failed'.
The fix mirrors the recovery pattern 'hermes gateway restart'
(systemd_restart) got in PR #20949: always reset-failed before
restart, on both the initial fallback and the retry. Also rewrites
the final failure message to tell the user to reset-failed +
restart (not just restart, which is the step that already failed
twice).
1d2029b2b7