Gate r4 quality: the store test's `<= _OBSERVABLE_METRIC_NAMES` assert only mirrored the constant, while the existing all-gauges-registered test's hand-built cron snapshot never got the two new gauges. Drop the constant re-check and add hermes.cron.store.writable / skipped_runs to that snapshot, so the parity check covers them (still red when either is unregistered).