docs: archive entra materials and simplify deployment docs

scripts/backup/database-backup.sh

@@ -38,10 +38,9 @@ if [ -n "$BACKUP_STORAGE_BUCKET" ]; then
   echo "Uploading backup to cloud storage..."
   if command -v aws &> /dev/null; then
     aws s3 cp "$BACKUP_FILE" "s3://$BACKUP_STORAGE_BUCKET/$(basename $BACKUP_FILE)" || true
-  elif command -v az &> /dev/null; then
-    az storage blob upload --file "$BACKUP_FILE" --container-name backups --name "$(basename $BACKUP_FILE)" --account-name "$AZURE_STORAGE_ACCOUNT" || true
+  elif [ -n "${BACKUP_CLOUD_SYNC_CMD:-}" ]; then
+    sh -c "$BACKUP_CLOUD_SYNC_CMD \"$BACKUP_FILE\" \"$BACKUP_STORAGE_BUCKET\"" || true
   fi
 fi
 
 echo "✅ Backup complete!"
-