fix: Prune=false guard on every PVC under a prune-enabled Application

Same protection already given to polymarket-bot postgres and n8n: without
it, removing a PVC manifest from git (rename, multi-doc refactor) would
make ArgoCD destroy the volume and its data.

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

researchowl/deployment.yaml

@@ -8,6 +8,9 @@ metadata:
 apiVersion: v1
 kind: PersistentVolumeClaim
 metadata:
+  annotations:
+    # Never let ArgoCD prune this PVC: it holds persistent app data.
+    argocd.argoproj.io/sync-options: Prune=false
   name: researchowl-data
   namespace: researchowl
 spec: