Verify-script: applied/ migrations vs live catalog diff

Close the loop on the §Unverifiable-State migration gap (pm-venus-cc GO 2026-07-30). venus applies DDL via execute_sql, so supabase_migrations.schema_migrations is stale (~venus48) and there is NO queryable path confirming a repo migration actually ran on prod. Build a one-shot verify script that introspects the live catalog (tables/columns/views/functions/indexes/triggers/grants) and diffs it against objects declared in db/migrations/applied/, reporting drift/undocumented DB-only objects, then stamps last-verified per section in db/state/venus-db-state.md. Not urgent; mirror doc landed first. Ref: venus/db/state/venus-db-state.md.