fix(manifests): prevent RWO PVC multi-attach errors during backend ro… (#853)

## Summary

Set `strategy.type: Recreate` on the `backend-api` deployment to prevent
multi-attach errors on the `backend-state-pvc` (ReadWriteOnce) during
rollouts on multi-node clusters.

## Problem

The backend deployment uses a RWO PVC (`backend-state-pvc`) for session
state persistence. With the default `RollingUpdate` strategy, the new
pod can be scheduled on a different node before the old pod fully
terminates and releases the volume, causing a multi-attach error that
blocks the deployment.

## Fix

`Recreate` strategy ensures the old pod is fully terminated (and its
volume detached) before the new pod is created. This is the
Kubernetes-recommended approach for deployments with RWO PVCs and is
consistent with the existing `replicas: 1` constraint.

## Test plan

- [ ] Deploy to multi-node cluster and verify rollout completes without
multi-attach errors

Fixes: [RHOAIENG-52353](https://issues.redhat.com/browse/RHOAIENG-52353)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: maskarb

components/manifests/base/backend-deployment.yaml

@@ -6,6 +6,8 @@ metadata:
     app: backend-api
 spec:
   replicas: 1  # Single pod for RWO PVC
+  strategy:
+    type: Recreate  # Required: RWO PVC cannot be multi-attached during rolling updates
   selector:
     matchLabels:
       app: backend-api