Hub defaultRules groups kubernetesSystemControllerManager, kubeScheduler, and
kubernetesSystemScheduler used wrong key 'enabled: false' — chart expects 'create: false'.
This caused KubeControllerManagerDown/KubeSchedulerDown to fire as false positives
because OTC CCE managed k8s does not expose control plane for scraping.
Dev local vmagent had empty externalLabels, so backup-alert rules evaluated by local
vmalert had no cluster_environment label on kube_job_status_failed metrics. Added
cluster_environment=dev to match what the vm-client-stack vmagent adds for hub shipping.
