Stranded queued runner jobs are reaped automatically

Runner jobs that never get picked up and stay showing “Queued” forever are now reaped automatically. A new background worker runs every 5 minutes and reconciles workflow jobs stranded in the queued phase against GitHub’s view: missed completed webhooks are reconciled with the real success/failure conclusion, deleted jobs are closed, legitimately running jobs are left alone, and jobs that GitHub itself still reports queued past 24 hours are force-closed as stale. The result: the Runners dashboard can no longer show jobs stuck in queued for days, and any row is guaranteed to reach a terminal state.