proxmox: Delete with seed cleanup, health Checker, CRD type comment

Delete stops and destroys a VM of ours under the per-name lock, then
deletes its seed on the VM's node, or on every node when no VM of ours
was left. A hibernated VM of ours is Permanent, as in Create. The
Checker verifies each node concurrently (version, node status, ISO
storage, templates) and adds CertificateInvalid, CredentialsUnavailable,
StorageNotFound and TemplateNotFound to the shared reasons. The
ProviderHealth type comment gains proxmox.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

api/v1alpha1/providerhealth_types.go

@@ -68,7 +68,7 @@ type ProviderTarget struct {
 // ProviderHealthStatus is the result of the latest check of one provider.
 type ProviderHealthStatus struct {
 	// type is the provider's type from the providers config: kubernetes,
-	// gcp, kvm or kvm2.
+	// gcp, kvm, kvm2 or proxmox.
 	// +optional
 	Type string `json:"type,omitempty"`