- fullSync/incrementalSync + getRoute53SyncService() singleton
- Paginated ListHostedZonesCommand + GetHostedZoneCommand (delegation set for D-12)
- Paginated ListResourceRecordSetsCommand per live zone
- Soft-delete reconciliation for zones and records (never hard-delete)
- sync_history bookkeeping with entity_type='route53', literal full/incremental sync_type
- Drift detection wired via buildDriftHistoryRows, writing sync_detected_drift history rows
- No integration_settings gating anywhere (D-10)
