fix(open-webui): add emptyDir volume for SQLite DB

Open WebUI crashes on startup because it can't write its SQLite database to
/app/backend/data.

- Add emptyDir volume at /app/backend/data
- Pod restarts will lose data (dev-only acceptable)

Fixes pod crash: peewee.OperationalError: unable to open database file

apps/base/customer1/hermes-agent/open-webui-deployment.yaml

@@ -54,6 +54,12 @@ spec:
           runAsUser: 1000
           seccompProfile:
             type: RuntimeDefault
+        volumeMounts:
+          - name: open-webui-data
+            mountPath: /app/backend/data
+      volumes:
+        - name: open-webui-data
+          emptyDir: {}
       securityContext:
         runAsNonRoot: true
         runAsUser: 1000