fix(storage): consolidate longhorn-kafka → unified longhorn StorageClass

Removes duplicate longhorn-kafka StorageClass managed by Kafka chart.
All applications now use single 'longhorn' StorageClass (3 replicas, Immediate binding).

Changes:
- Kafka chart: use 'longhorn' instead of 'longhorn-kafka'
- Delete Kafka StorageClass template (no longer needed)
- Update longhorn-storageclass.yaml to match deployed config (Immediate, not WaitForFirstConsumer)

Existing Kafka PVCs remain bound to old longhorn-kafka StorageClass (safe - no data loss).
New PVCs will use unified 'longhorn' StorageClass.

k8s/applications/sqs/charts/kafka-cluster/templates/storageclass.yaml

@@ -1,19 +0,0 @@
-{{- if eq .Values.nodePool.storage.class "longhorn-kafka" }}
-# The default "longhorn" StorageClass requests 3 replicas across 3 zone-labeled
-# nodes (az-a/az-b/az-c). With Longhorn's zone-aware anti-affinity, replicas
-# spread 1-per-zone for durability.
-apiVersion: storage.k8s.io/v1
-kind: StorageClass
-metadata:
-  name: longhorn-kafka
-provisioner: driver.longhorn.io
-allowVolumeExpansion: true
-reclaimPolicy: Delete
-volumeBindingMode: Immediate
-parameters:
-  numberOfReplicas: "3"
-  staleReplicaTimeout: "30"
-  fromBackup: ""
-  fsType: "ext4"
-  dataLocality: "disabled"
-{{- end }}

k8s/applications/sqs/charts/kafka-cluster/values.yaml

@@ -4,7 +4,7 @@ namespace: sqs
 nodePool:
   replicas: 3
   storage:
-    class: longhorn-kafka
+    class: longhorn
     # Longhorn's per-node scheduling budget on the current 2-node cluster has
     # only ~36Gi of headroom left (other PVCs already reserve the rest), and
     # each node hosts one replica of all 3 broker volumes -- so 3 * sizeGi

k8s/applications/sqs/environments/homelab.yaml

@@ -7,8 +7,8 @@ kafkaCluster:
   nodePool:
     replicas: 3
     storage:
-      # longhorn-kafka now uses numberOfReplicas: 3 across 3 zone-labeled nodes.
-      class: longhorn-kafka
+      # Use unified longhorn StorageClass (3 replicas, Immediate binding)
+      class: longhorn
       # Per-node headroom: with 3 nodes and existing PVCs, estimate ~100+ Gi total
       # available. Each node hosts one replica of all 3 broker volumes, so 3 *
       # sizeGi must fit. Monitor usage during Kafka deployment.

k8s/infrastructure/longhorn/longhorn-storageclass.yaml

@@ -10,12 +10,12 @@ metadata:
 provisioner: driver.longhorn.io
 allowVolumeExpansion: true
 reclaimPolicy: Delete
-volumeBindingMode: WaitForFirstConsumer  # Wait for pod scheduling before binding
+volumeBindingMode: Immediate  # Immediate binding for StatefulSets (matches deployed config)
 parameters:
   numberOfReplicas: "3"           # HA across all 3 nodes
   staleReplicaTimeout: "30"
   fromBackup: ""
-  dataLocality: "best-effort"     # Prefer local replica when possible
+  dataLocality: "disabled"        # Match deployed config (not best-effort)
   fsType: "ext4"
   disableRevisionCounter: "true"  # Performance optimization
   unmapMarkSnapChainRemoved: "ignored"