Gateway restart did not erase the sync backlog: unsynced `buffered_sync_items` count
remained at 5 through the container restart because the ward PostgreSQL database is
independent of the API process lifecycle. After central API was restarted, sync resumed
automatically — all three experiment observations (`gateway-restart-exp6-1782246096-*`)
appeared on central and the buffer drained to 0 within 120 seconds. This validates the
UPS + ward-server deployment model: brief gateway process restarts (deployments, OOM kills)
do not lose clinical events already accepted at the bedside.