worker_ready signal handler was NOT firing in our setup (verified via
DB breadcrumb after 3 deploys — zero rows of stage='worker_ready' in
nspd_geo_log). Root cause of unreliability unknown — possibly Celery
internals, possibly compose recreate timing. Either way, after every
redeploy users had to manually cancel/resume jobs to keep them moving.
Replace signal-based resume with periodic beat task:
- cleanup_zombies runs every minute (* * * * *)
- Finds nspd_geo_jobs in status running/paused with heartbeat >2 min stale
- Sets status='queued' + apply_async with queue=geo
- Idempotent — if no zombies, no-op
worker_ready handler kept (with FK-fix breadcrumb on NULL job_id) for
diagnostic purposes — if signal ever does fire, we'll have evidence.
caa467fb7e