CVE-2026-65834: Capsule: CapsuleConfiguration NodeMetadata regex fields lack webhook validation, allowing MustCompile panic on all Node admission requests

CapsuleConfiguration.Spec.NodeMetadata.ForbiddenLabels.Regex and ForbiddenAnnotations.Regex are never validated by any admission webhook. A Cluster Admin can persist a malformed regex to etcd without being blocked. Once stored, every Node CREATE, UPDATE, or PATCH request triggers regexp.MustCompile() in pkg/api/forbidden_list.go:36, which panics and crashes the node admission webhook — causing a cluster-wide Denial of Service for all Node operations.