4035c44be3
Schedules tab Run-now used to silently HX-Redirect back to the
list, leaving the operator wondering whether the click registered.
Now:
* Single-source-group schedule → HX-Redirect to that one job's
live log, matching the per-source-group Run-now UX from Sources.
* Multi-group schedule → stay on the schedules list and fire a
success toast ("N backups dispatched: <group names>") via the
existing rm:toast HX-Trigger channel, so the operator sees clear
acknowledgement without losing their place.
dispatchBackupForGroup now returns the persisted job ID so the
caller can choose between job-log redirect and toast feedback;
on any internal failure it returns "" and the warning still
hits slog as before. The cron-fired path (dispatchScheduledJob)
ignores the return value, behaviour unchanged.