fix(iam): persist revocations across site replay and recovery

Retain source-ordered tombstones and parent grant boundaries across both IAM backends, cache reloads, and deliberate identity recreation. Reconcile deletions through a versioned, bounded replication protocol with restart-aware acknowledgements.

Cover inherited group grants, STS retention, same-key service recreation, absolute expiration, and failures after the durable commit. Document coordinated upgrades and the remaining consistency boundaries.

Signed-off-by: Feng Ruohang <rh@vonng.com>

cmd/metrics-v3.go

@@ -323,6 +323,10 @@ func newMetricGroups(r *prometheus.Registry) *metricsV3Collection {
 			sinceLastSyncMillisMD,
 			syncFailuresMD,
 			syncSuccessesMD,
+			revocationRecordsMD,
+			revocationHealFailuresMD,
+			revocationHealDurationMillisMD,
+			revocationHealLastSuccessMD,
 		},
 		loadClusterIAMMetrics,
 	)