k8s/messaging: add kafka kmsvc and temporal workflows

- Kafka 3-broker cluster (RF=3, min-ISR=2)
- kmsvc SQS-like API on Kafka
- Redis dedup (standalone, can extend to HA)
- Temporal workflow orchestration (Cassandra backend)

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

@@ -0,0 +1,19 @@
+{{- 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 }}