fix(prometheus): use Recreate strategy to avoid Multi-Attach on RWO PVC

Prometheus server runs as a single-replica Deployment with an RWO PVC.
RollingUpdate starts the new pod before the old releases the volume,
which fails with Multi-Attach on rollouts and reschedules.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

infra/values/base/prometheus-values.yaml

@@ -4,6 +4,9 @@ server:
   service:
     servicePort: 80
 
+  strategy:
+    type: Recreate
+
   resources:
     requests:
       cpu: 150m