- Header shows a live sync status (total videos + channels still backfilling, or
"paused"), polled every 30s
- Admins can pause/resume the background sync; a paused flag in app_state makes
scheduled jobs skip (migration 0006)
- GET /api/feed/count returns the number of videos matching the current filters;
shared filter builder keeps it in sync with /api/feed; shown above the feed
- /api/sync/status reports backfill progress, pending enrichment and paused state
