Standardize deployment env and deployer handling

scripts/deployment/deploy-weth-create.sh

@@ -30,16 +30,10 @@ fi
 RPC_URL="${RPC_URL:-http://localhost:8545}"
 PRIVATE_KEY="${PRIVATE_KEY:-}"
 
-if [ -z "$PRIVATE_KEY" ]; then
-    echo "Error: PRIVATE_KEY environment variable not set"
+if ! require_private_key_env; then
     exit 1
 fi
 
-# Ensure PRIVATE_KEY has 0x prefix
-if [[ ! "$PRIVATE_KEY" =~ ^0x ]]; then
-    export PRIVATE_KEY="0x$PRIVATE_KEY"
-fi
-
 echo "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"
 echo "🚀 Deploying WETH9 and WETH10 using CREATE (vm.etch)"
 echo "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"
@@ -135,4 +129,3 @@ echo "   1. If deployment failed, try using fork mode: --fork-url \$RPC_URL"
 echo "   2. Or calculate CREATE nonce: node scripts/utils/calculate-create-address.js"
 echo "   3. Or use address mapping for deployed addresses"
 echo ""
-