Wraps systemctl list-timers with the things you actually want when checking on
the build host: per-unit enabled state, last run and whether it succeeded,
which channels have builds queued (state files), whether the release lock is
held by a live process, and any failed units. Units are discovered from
systemd/*.timer so the report cannot drift from what setup installs.
It forwards over ssh like the other host commands, so the build box's timer
state is one command away from a workstation (--local to inspect this machine).