feat: add memory service queues (processing, indexing, dlq)

- processing-queue: high-throughput, auto-scaling (1-4 shards)
- indexing-queue: FIFO with deduplication (1-2 shards)
- memory-dlq: dead letter queue for redelivery failures
- ArgoCD Application (wave 7) to auto-sync queue lifecycle

k8s/argocd/apps/50-memory-queues.yaml

@@ -0,0 +1,20 @@
+apiVersion: argoproj.io/v1alpha1
+kind: Application
+metadata:
+  name: memory-queues
+  namespace: argocd
+  annotations:
+    argocd.argoproj.io/sync-wave: "7"
+spec:
+  project: homelab
+  source:
+    repoURL: https://forgejo.riotpiao.com/rock/homelab.git
+    targetRevision: main
+    path: k8s/apps/messaging/memory-queues
+  destination:
+    server: https://kubernetes.default.svc
+    namespace: sqs
+  syncPolicy:
+    automated:
+      prune: true
+      selfHeal: true