build(deps-dev): add es-main

This module provides an equivalent to `require.main === module` for ECMAScript modules.
See nodejs/node#49440

This module is imported in testPrep.mts

Author: BinToss

package-lock.json

@@ -116,6 +116,7 @@
     "@typescript-eslint/parser": "5.48.0",
     "@vitest/coverage-v8": "^1.4.0",
     "cross-env": "7.0.3",
+    "es-main": "1.3.0",
     "esbuild": "0.16.13",
     "eslint": "8.57.0",
     "eslint-config-prettier": "9.1.0",