Kradle ExternalBackendSyncPolicy overview

ExternalBackendSyncPolicy defines sync direction, cadence, conflict rules, and write permissions for an external backend integration. It is owned by the external-backends service and participates in provider synchronization. It is owned by the policy service and participates in admission, approval, or governance evidence. Atlas models it as a external-backend CRD with Namespaced scope, v1alpha1 storage version, and source-backed Kubernetes API metadata so controller, policy, UI/API, and provider edges can target the exact resource kind.