Add the cluster-scoped ProviderHealth CRD

One operator-owned object per configured provider will carry the
periodic check result: a Ready condition, per-target verdicts with their
own transition times, and a ready/total count for kubectl get. There is
no spec; only a viewer role is shipped since the operator is the sole
writer. Written by hand (kubebuilder is not installed), registered in
the existing AddKnownTypes call rather than a second init().

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

config/crd/kustomization.yaml

@@ -3,4 +3,5 @@
 # It should be run by config/default
 resources:
 - bases/crawl.example.com_proxies.yaml
+- bases/crawl.example.com_providerhealths.yaml
 # +kubebuilder:scaffold:crdkustomizeresource