fix(secrets-backup): 🐛 add openssl install + upgrade image to 1.32.0

alpine/k8s:1.28.0 does not ship openssl. Script calls openssl enc
on line 116 causing exit 127 on every run since initial deploy.

Fix:
- apk add --no-cache openssl at script start (defensive, idempotent)
- upgrade image 1.28.0 -> 1.32.0 (kubectl client was 5 minor versions
  behind cluster v1.33, outside supported skew of +/-1)

otc/dev.t09.de/stacks/core/secrets-backup/manifests/secrets-backup-cronjob.yaml

@@ -61,7 +61,7 @@ spec:
           serviceAccountName: secrets-backup
           containers:
             - name: secrets-backup
-              image: alpine/k8s:1.28.0
+              image: alpine/k8s:1.32.0
               imagePullPolicy: IfNotPresent
               env:
                 - name: AWS_ACCESS_KEY_ID
@@ -92,6 +92,9 @@ spec:
                 - |
                   set -euo pipefail
 
+                  # Ensure openssl is available (not bundled in alpine/k8s image)
+                  apk add --no-cache openssl --quiet
+
                   TIMESTAMP=$(date +%Y%m%d-%H%M%S)
                   BACKUP_DIR="/tmp/secrets-backup-${TIMESTAMP}"
                   NAMESPACES="argocd cert-manager external-secrets"