fix(babylonlabs-io-btc-staking-ts): add BitGo-specific exports

Add exports for babylon and staking utility functions needed by BitGo
integration code.

Issue: BTC-2143

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

Author: 2 people

modules/babylonlabs-io-btc-staking-ts/src/index.ts

@@ -15,3 +15,7 @@ export {
 export * from "./utils/utxo/findInputUTXO";
 export * from "./utils/utxo/getPsbtInputFields";
 export * from "./utils/utxo/getScriptType";
+
+// BitGo-specific exports
+export * from "./utils/babylon";
+export * from "./utils/staking";