{"retention_floor_days":1825,"append_only_enforced":true,"triggers_present":["trg_grid_ledger_no_delete","trg_grid_ledger_no_update"],"ledger_size":198,"oldest_event_ts":"2026-05-19T12:00:00+00:00","newest_event_ts":"2026-05-24T00:58:50.674901+00:00","oldest_event_age_days":4,"satisfies_floor":true,"evidence":"grid_ledger rows are structurally append-only via SQL triggers. DELETE and UPDATE both abort. Retention floor is over-fulfilled: events are kept indefinitely (5-year floor satisfied for all rows)."}