fix(esm): improve ESM compatibility and modernize package configuration

test/test.node.ts

@@ -0,0 +1,7 @@
+import { expect, tap } from '@git.zone/tstest/tapbundle';
+
+import * as smartspawn from '../ts/index.js';
+
+tap.test('should create a simple test function', async () => {});
+
+export default tap.start();