Two bugs caused the domainRealtime channel to fail with CHANNEL_ERROR and
reconnect-loop every 3s (which also dragged down the notifRealtime channel via
the shared websocket close):
1. useDomainSubmissionRealtime.ts filtered domain_submissions on a column that
doesn't exist (`submitter_id`) — the actual column is `user_id`. Postgres
raised on the publication-side filter registration → CHANNEL_ERROR.
2. rebreak.user_custom_domains was never added to the supabase_realtime
publication — the channel also subscribes to that table. New migration
20260511_fix_realtime_user_custom_domains adds it.
(Diagnosis via backyard agent against the self-hosted Supabase on the Hetzner box.)
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
