feat(megaeth): add MegaETH mainnet and testnet support

- Add MegaETH mainnet (Chain ID: 4326) network configuration
- Fix MegaETH testnet chain ID from 6342 to 6343
- Update testnet explorer to use Etherscan v2 API
- Add EIP-1559 gas configuration for MegaETH
- Add MegaETH-specific gas estimation handling in deploy script

Ticket: WIN-8361

Author: manojkumar138

config/chainIds.ts

@@ -86,7 +86,7 @@ export const CHAIN_IDS = {
   KAVAEVM_TESTNET: 2221,
   PLUME_TESTNET: 98867,
   FLOW_TESTNET: 545,
-  MEGAETH_TESTNET: 6342,
+  MEGAETH_TESTNET: 6343,
   HBAREVM_TESTNET: 296,
   FLUENTETH_TESTNET: 20994,
   MANTLE_TESTNET: 5003,

hardhat.config.ts

@@ -1528,8 +1528,8 @@ const config: HardhatUserConfig = {
         network: 'megaethTestnet',
         chainId: CHAIN_IDS.MEGAETH_TESTNET,
         urls: {
-          apiURL: 'https://carrot.megaeth.com/mafia/api',
-          browserURL: 'https://www.megaexplorer.xyz/'
+          apiURL: `${ETHERSCAN_V2_URL}${CHAIN_IDS.MEGAETH_TESTNET}`,
+          browserURL: 'https://testnet-mega.etherscan.io/'
         }
       },
       {

scripts/chainConfig.ts

@@ -246,6 +246,17 @@ export async function getChainConfig(chainId: number): Promise<ChainConfig> {
       break;
 
     case CHAIN_IDS.MEGAETH_TESTNET:
+    case CHAIN_IDS.MEGAETH:
+      // MegaETH: Must use EIP-1559 params with high gas limit
+      // Gas price is very low (~0.001 Gwei), so high limit is cheap
+      gasParams = {
+        maxFeePerGas: feeData.maxFeePerGas ?? 2_000_000n,
+        maxPriorityFeePerGas: feeData.maxPriorityFeePerGas ?? 1_000_000n,
+        gasLimit: 30_000_000 // MegaETH needs higher gas limits
+      };
+      forwarderContractName = 'ForwarderV4';
+      forwarderFactoryContractName = 'ForwarderFactoryV4';
+      break;
 
     case CHAIN_IDS.HBAREVM:
     case CHAIN_IDS.HBAREVM_TESTNET:

scripts/deploy.ts

@@ -29,7 +29,17 @@ async function main() {
   const chainConfig = await getChainConfig(Number(chainId));
   const output: DeploymentAddresses = loadOutput();
 
-  const gasOverrides = chainConfig.gasParams;
+  let gasOverrides: any = chainConfig.gasParams;
+
+  // MegaETH chains: remove gasLimit to let network auto-estimate (required for MegaETH)
+  const MEGAETH_CHAINS = [4326, 6343]; // mainnet and testnet
+  if (MEGAETH_CHAINS.includes(Number(chainId))) {
+    const { gasLimit, ...gasOverridesWithoutLimit } = gasOverrides;
+    gasOverrides = gasOverridesWithoutLimit;
+    console.log(
+      'ℹ️  MegaETH detected: using auto gas estimation (no gasLimit)'
+    );
+  }
 
   // Handle BigBlocks setup automatically if supported
   if (isBigBlocksSupported(Number(chainId))) {
@@ -47,22 +57,34 @@ async function main() {
   // Estimate gas costs for all potential deployments
   let totalEstimatedCost = 0n;
 
-  // For chains with very high gas limits (like Mantle), skip estimation and use configured limit
-  const useConfiguredGasLimit = gasOverrides.gasLimit > 10_000_000_000; // > 10 billion
+  // For chains with very high gas limits (like Mantle) or chains with estimation issues (like MegaETH)
+  // skip estimation and use configured limit
+  const CHAINS_SKIP_ESTIMATION = [4326, 6343]; // MegaETH mainnet and testnet
+  const isMegaETH = CHAINS_SKIP_ESTIMATION.includes(Number(chainId));
+  const useConfiguredGasLimit =
+    (gasOverrides.gasLimit && gasOverrides.gasLimit > 10_000_000_000) ||
+    isMegaETH;
 
-  if (useConfiguredGasLimit) {
+  if (useConfiguredGasLimit && !isMegaETH) {
     console.log(
       `⚠️  Using configured gas limit (${gasOverrides.gasLimit}) instead of estimation for this chain`
     );
+  } else if (isMegaETH) {
+    console.log(
+      'ℹ️  MegaETH: skipping gas estimation, will use auto-estimation during deployment'
+    );
   }
 
   // Only estimate if we need to deploy (not already deployed)
   if (
     !output.walletImplementation ||
     !(await isContractDeployed(output.walletImplementation))
   ) {
-    if (useConfiguredGasLimit) {
+    if (useConfiguredGasLimit && gasOverrides.gasLimit) {
       totalEstimatedCost += BigInt(gasOverrides.gasLimit);
+    } else if (isMegaETH) {
+      // Skip estimation for MegaETH - use reasonable default for cost check
+      totalEstimatedCost += BigInt(3_000_000);
     } else {
       const WalletSimple = await ethers.getContractFactory(
         chainConfig.walletImplementationContractName
@@ -79,8 +101,10 @@ async function main() {
     !output.walletFactory ||
     !(await isContractDeployed(output.walletFactory))
   ) {
-    if (useConfiguredGasLimit) {
+    if (useConfiguredGasLimit && gasOverrides.gasLimit) {
       totalEstimatedCost += BigInt(gasOverrides.gasLimit);
+    } else if (isMegaETH) {
+      totalEstimatedCost += BigInt(3_000_000);
     } else {
       const WalletFactory = await ethers.getContractFactory(
         chainConfig.walletFactoryContractName
@@ -100,8 +124,10 @@ async function main() {
     !output.forwarderImplementation ||
     !(await isContractDeployed(output.forwarderImplementation))
   ) {
-    if (useConfiguredGasLimit) {
+    if (useConfiguredGasLimit && gasOverrides.gasLimit) {
       totalEstimatedCost += BigInt(gasOverrides.gasLimit);
+    } else if (isMegaETH) {
+      totalEstimatedCost += BigInt(3_000_000);
     } else {
       const ForwarderV4 = await ethers.getContractFactory(
         chainConfig.forwarderContractName
@@ -118,8 +144,10 @@ async function main() {
     !output.forwarderFactory ||
     !(await isContractDeployed(output.forwarderFactory))
   ) {
-    if (useConfiguredGasLimit) {
+    if (useConfiguredGasLimit && gasOverrides.gasLimit) {
       totalEstimatedCost += BigInt(gasOverrides.gasLimit);
+    } else if (isMegaETH) {
+      totalEstimatedCost += BigInt(3_000_000);
     } else {
       const ForwarderFactory = await ethers.getContractFactory(
         chainConfig.forwarderFactoryContractName