feat: prepare ARR for controlled public deployment

database/009_source_read_grants.down.sql

@@ -0,0 +1,16 @@
+-- Manual rollback for migration 009. Never run as part of normal startup.
+
+BEGIN;
+
+DO $$
+BEGIN
+    IF current_database() <> 'booking_test' THEN
+        RAISE EXCEPTION
+            'ARR source read grant rollback is allowed only in booking_test';
+    END IF;
+END;
+$$;
+
+DROP TABLE ingestion.source_read_grants;
+
+COMMIT;