GET /not-found API endpoint to list services with unresolvable local digests

Updater poll spam: when local image digest cannot be resolved, the updater no longer calls deploy every poll cycle. A notFound suppression map tracks the remote digest at time of failure and silences retries until the registry digest changes

Healer noise during deploys: handleHealthy now checks IsDeploying() to suppress spurious “Container recovered and is healthy” notifications during legitimate deploys