fix(prometheus): use longhorn StorageClass, drop nonexistent longhorn-wffc — Prometheus CR requested storageClass longhorn-wffc which doesn't exist (deprecated), so operator never created the StatefulSet (Reconciled=False, no metrics server)

k8s/infra/longhorn/longhorn-storageclass.yaml

@@ -1,5 +1,5 @@
-# Longhorn StorageClass - single unified storage class for the entire cluster
-# Replaces: longhorn-wffc, longhorn-kafka, longhorn-static (all deprecated)
+# Longhorn StorageClass - single unified `longhorn` storage class for the whole
+# cluster. This is the only Longhorn class anything should reference.
 apiVersion: storage.k8s.io/v1
 kind: StorageClass
 metadata:

k8s/infra/monitoring/prometheus-values.yaml

@@ -42,12 +42,12 @@ prometheus:
       topology.kubernetes.io/zone: az-a
 
     # Persistent storage — metrics survive node reboots and pod restarts.
-    # longhorn-wffc (WaitForFirstConsumer) binds after scheduling so the volume
-    # lands on the node the pod runs on.
+    # Uses the default `longhorn` StorageClass; nodeSelector above already pins
+    # the pod to az-a (the sole Longhorn node), so Immediate binding is fine.
     storageSpec:
       volumeClaimTemplate:
         spec:
-          storageClassName: longhorn-wffc
+          storageClassName: longhorn
           accessModes: ["ReadWriteOnce"]
           resources:
             requests: