monitoring(probe): signage/mysql/php blackbox probe / -> /healthz (K8s-target mirror)

Mirrors the live noc1 podman fix + Notes scripts/monitoring/prometheus.yml.
These services enforce OIDC bearer auth (FlowerCore__Auth__Enabled=true), so an
anonymous probe of / returns 401 -> false TraefikServiceDown. All three expose
anonymous /healthz=200. This noc-monitoring.yaml is the forward K8s-migration
target (not live); brings it in sync with the live config.

apps/monitoring/noc-monitoring.yaml

@@ -479,11 +479,11 @@ data:
               - "https://gitea.iamworkin.lan/"
               - "https://argocd.iamworkin.lan/"
               - "https://intranet.iamworkin.lan/"
-              - "https://signage.iamworkin.lan/"
+              - "https://signage.iamworkin.lan/healthz"   # root 401 auth-gated 2026-06-01; /healthz anon 200
               - "https://kiosk.iamworkin.lan/"
               - "https://media.iamworkin.lan/"
-              - "https://mysql.iamworkin.lan/"
-              - "https://php.iamworkin.lan/"
+              - "https://mysql.iamworkin.lan/healthz"   # root 401 auth-gated 2026-06-01; /healthz anon 200
+              - "https://php.iamworkin.lan/healthz"     # root 401 auth-gated 2026-06-01; /healthz anon 200
               - "https://zabbix.iamworkin.lan/"
               - "https://desktop.iamworkin.lan/"
               - "https://print.iamworkin.lan/"