chore: build message sample script

TICKET: COIN-4593

Author: bhavidhingra

examples/ts/build-message.ts

@@ -0,0 +1,38 @@
+/**
+ * Pre-build a message from the wallet
+ *
+ * This tool will help you see how to use the BitGo API to easily build
+ * a message from a wallet.
+ *
+ * Copyright 2025, BitGo, Inc.  All Rights Reserved.
+ */
+
+import {BitGoAPI} from '@bitgo/sdk-api';
+import {Hteth} from "@bitgo/sdk-coin-eth";
+import {MessageStandardType} from "@bitgo/sdk-core"; // Replace with your given coin (e.g. Ltc, Tltc)
+require('dotenv').config({ path: '../../.env' });
+
+const bitgo = new BitGoAPI({
+  accessToken: process.env.TESTNET_ACCESS_TOKEN,
+  env: 'test', // Change this to env: 'production' when you are ready for production
+});
+
+// Set the coin name to match the blockchain and network
+// doge = dogecoin, tdoge = testnet dogecoin
+const coin = 'hteth';
+bitgo.register(coin, Hteth.createInstance);
+
+const id = '';
+
+async function main() {
+  const wallet = await bitgo.coin(coin).wallets().get({ id });
+  console.log(`Wallet label: ${wallet.label()}`);
+
+  const txRequest = await wallet.createSignMessageRequest({
+    messageRaw: 'Hello, BitGo!',
+    messageStandardType: MessageStandardType.EIP191,
+  });
+  console.dir(txRequest);
+}
+
+main().catch((e) => console.log(e));