Mirror the strict unit-name shape from the hermes-serve gate (review on
PR #83595) on the gateway side too: the discovery gate and the SIGUSR1
eligibility helper now accept only `hermes-gateway.service` or the
`hermes-gateway-<profile>` family, so a near-prefix unit like
`hermes-gatewayd.service` can neither enter the restart path nor be sent
a SIGUSR1 it does not handle.
Review on #83595 flagged two service-lifecycle gaps in the hermes-serve
restart support:
- The unit-name gate accepted anything starting with "hermes-serve",
which also matched the unrelated hermes-server.service. Require the
exact base unit or the hyphenated profile family instead.
- The fleet-restart loop and _finish_dashboard_update_cleanup() could
both restart the same hermes-serve unit — the loop restarts it
directly, then cleanup's PID scan finds the fresh process and
restarts its owning unit again. Thread the fleet loop's restarted
unit names through to _kill_stale_dashboard_processes() so it skips
units already handled.
hermes update discovered and restarted hermes-gateway* systemd units but
never looked for hermes-serve* — the Desktop app's backend — so it kept
running stale pre-update code until the user restarted it by hand (#83438).
Extend the systemd unit discovery/restart loop to also match hermes-serve*
units. They don't wire SIGUSR1 to a graceful drain (only gateway/run.py
does), so restart eligibility for the graceful path is now gated on unit
name via a small, directly-tested helper; hermes-serve units fall straight
to the existing blunt systemctl restart path, matching the workaround the
issue already documents.