feat(n8n): enable prune, guarded by Prune=false on the workflows PVC

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

argocd/application-n8n.yaml

@@ -23,6 +23,7 @@ spec:
     targetRevision: main
   syncPolicy:
     automated:
+      prune: true
       selfHeal: true
     syncOptions:
     - CreateNamespace=true

n8n/pvc-n8n-pvc.yaml

@@ -1,6 +1,9 @@
 apiVersion: v1
 kind: PersistentVolumeClaim
 metadata:
+  annotations:
+    # Never let ArgoCD prune this PVC: it holds the n8n workflows database.
+    argocd.argoproj.io/sync-options: Prune=false
   name: n8n-pvc
   namespace: n8n
 spec: