Switch hook jobs from bitnami/kubectl to alpine/k8s:1.32.13

bitnami/kubectl has removed all version tags from Docker Hub,
leaving only :latest which is blocked by Kyverno disallow-latest-tag
policy. Switch to alpine/k8s:1.32.13 which has kubectl, bash, jq,
and uses proper version tags.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

infrastructure/vault/manifests/vault-init-job.yaml

@@ -14,7 +14,7 @@ spec:
       serviceAccountName: argocd-hook-sa
       containers:
         - name: vault-init
-          image: bitnami/kubectl:1.29
+          image: alpine/k8s:1.32.13
           command: ["/bin/bash", "/scripts/vault-init-and-store.sh"]
           volumeMounts:
             - name: scripts