feat(otc): 🛡️ default StorageClass reclaimPolicy to Retain

Prevents accidental data loss on PVC deletion. Volumes persist even
when PVC is removed. Ephemeral environments can override via
STORAGE_RECLAIM_POLICY=Delete env var.

Ref: IPCEICIS-2810

template/stacks/otc/storageclass/storageclass.yaml

@@ -13,6 +13,6 @@ parameters:
   kubernetes.io/volumetype: SATA
   kubernetes.io/zone: eu-de-02
 provisioner: flexvolume-huawei.com/fuxivol
-reclaimPolicy: Delete
+reclaimPolicy: {{{ getenv "STORAGE_RECLAIM_POLICY" "Retain" }}}
 volumeBindingMode: Immediate
 allowVolumeExpansion: true