feat(abstract-utxo): use correct script hash for testnet LTC addresses

Fix the cross-chain recovery address conversion to properly handle testnet
Litecoin addresses by using the correct script hash value. Previously, the
code was using Bitcoin mainnet's script hash for both mainnet and testnet
Litecoin addresses, which caused incorrect conversions for testnet.

Also added a check to skip processing for non-Litecoin coins and expanded
tests to verify both mainnet and testnet address conversions.

Issue: BTC-2891

Co-authored-by: llm-git <llm-git@ttll.de>

Author: OttoAllmendinger

modules/abstract-utxo/src/recovery/crossChainRecovery.ts

@@ -123,6 +123,10 @@ export async function isWalletAddress(wallet: IWallet | WalletV1, address: strin
  * @returns The address in legacy 3... format, or the original address if it's not a P2SH address
  */
 export function convertLtcAddressToLegacyFormat(address: string, coinName: UtxoCoinName): string {
+  if (coinName !== 'ltc' && coinName !== 'tltc') {
+    return address;
+  }
+
   const network = getNetworkFromCoinName(coinName);
   try {
     // Try to decode as bech32 - these don't need conversion
@@ -137,7 +141,8 @@ export function convertLtcAddressToLegacyFormat(address: string, coinName: UtxoC
     // Only convert P2SH addresses (scriptHash), not P2PKH (pubKeyHash)
     if (decoded.version === network.scriptHash) {
       // Convert to legacy format using Bitcoin's scriptHash (0x05)
-      const legacyScriptHash = utxolib.networks.bitcoin.scriptHash;
+      const legacyScriptHash =
+        coinName === 'ltc' ? utxolib.networks.bitcoin.scriptHash : utxolib.networks.testnet.scriptHash;
       return utxolib.address.toBase58Check(decoded.hash, legacyScriptHash, network);
     }
     // P2PKH or other - return unchanged

modules/abstract-utxo/test/unit/recovery/crossChainRecovery.ts

@@ -5,6 +5,7 @@ import nock = require('nock');
 import * as utxolib from '@bitgo/utxo-lib';
 import { Triple } from '@bitgo/sdk-core';
 import { getSeed } from '@bitgo/sdk-test';
+import { address as wasmAddress } from '@bitgo/wasm-utxo';
 import * as sinon from 'sinon';
 
 import {
@@ -318,15 +319,24 @@ describe(`Cross-Chain Recovery getWallet`, async function () {
 });
 
 describe('convertLtcAddressToLegacyFormat', function () {
+  const scriptPubKey = Buffer.from('a9149f0bf51fab4d33ab21977e1b89f776f64161ef4287', 'hex');
   it('should convert M... P2SH address to 3... legacy format', function () {
     // These two addresses represent the same underlying script hash:
     // - MNQ7zkgMsaV67rsjA3JuP59RC5wxRXpwgE is the LTC format (scriptHash 0x32)
     // - 3GBygsGPvTdfKMbq4AKZZRu1sPMWPEsBfd is the BTC format (scriptHash 0x05)
-    const ltcAddress = 'MNQ7zkgMsaV67rsjA3JuP59RC5wxRXpwgE';
-    const expectedLegacyAddress = '3GBygsGPvTdfKMbq4AKZZRu1sPMWPEsBfd';
+    // const ltcAddress = 'MNQ7zkgMsaV67rsjA3JuP59RC5wxRXpwgE';
+    const ltcAddress = wasmAddress.fromOutputScriptWithCoin(scriptPubKey, 'ltc');
+    const tltcAddress = wasmAddress.fromOutputScriptWithCoin(scriptPubKey, 'tltc');
+    assert.strictEqual(ltcAddress, 'MNQ7zkgMsaV67rsjA3JuP59RC5wxRXpwgE');
+    assert.strictEqual(tltcAddress, 'Qb6wsd4fZ2C6fKzRMPyTG5KiE81W6QCxhU');
 
     const legacyAddress = convertLtcAddressToLegacyFormat(ltcAddress, 'ltc');
-    assert.strictEqual(legacyAddress, expectedLegacyAddress);
+    const expectedLtcLegacyAddress = '3GBygsGPvTdfKMbq4AKZZRu1sPMWPEsBfd';
+    assert.strictEqual(legacyAddress, expectedLtcLegacyAddress);
+
+    const expectedTltcLegacyAddress = '2N7kBkcCRXv91X9ENjHwSBNtH5jZg8yye6r';
+    const tltcLegacyAddress = convertLtcAddressToLegacyFormat(tltcAddress, 'tltc');
+    assert.strictEqual(tltcLegacyAddress, expectedTltcLegacyAddress);
   });
 
   it('should convert MD68PsdheKxcYsrVLyZRXgoSDLnB1MdVtE to legacy format', function () {