Standardize deployment env and deployer handling

scripts/deployment/deploy-weth-create2.sh

@@ -29,16 +29,10 @@ 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 CREATE2"
 echo "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"
@@ -149,4 +143,3 @@ echo "📋 Next Steps:"
 echo "   1. Verify contract functionality"
 echo "   2. Update .env with deployment details if needed"
 echo ""
-