Standardize deployment env and deployer handling

scripts/deployment/deploy-vault-system-and-ac-vdc-sdc.sh

@@ -28,13 +28,9 @@ RPC_URL="${RPC_URL_138:-http://192.168.11.211:8545}"
 GAS_PRICE="${GAS_PRICE:-1000000000}"
 CHAIN_ID="${CHAIN_ID:-138}"
 
-if [ -z "$PRIVATE_KEY" ]; then
-    echo "Error: PRIVATE_KEY not set (e.g. in smom-dbis-138/.env)"
+if ! require_private_key_env; then
     exit 1
 fi
-if [[ ! "$PRIVATE_KEY" =~ ^0x ]]; then
-    export PRIVATE_KEY="0x$PRIVATE_KEY"
-fi
 
 echo "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"
 echo "1. Deploy Vault System (DeployVaultSystem.s.sol)"