Enable full ESM support for Node 20+ and modern dependencies, update Jest and build output configuration

- Set "type": "module" in package.json to enable ESM throughout the project.
- Changed "main" in package.json to "dist/index.js" to point to the bundled output generated by ncc.
- Updated Jest configuration (jest.config.js) to ESM format and to use babel-jest for TypeScript transformation.
- Added/updated babel.config.js in ESM format to support TypeScript and ESM for Jest.
- Ensured test scripts use NODE_OPTIONS=--experimental-vm-modules for Jest ESM compatibility.

jest.config.js

@@ -1,21 +1,15 @@
-/** @type {import('ts-jest/dist/types').InitialOptionsTsJest} */
-module.exports = {
-    transform: {
-      "^.+\\.tsx?$": "ts-jest",
-      "^.+\\.[t|j]sx?$": "babel-jest", // Use Babel for transforming JS and TS files
-      "^.+\\.mjs$": "jest-transform-stub",  // Use the stub to handle ES modules
-    },
-    preset: 'ts-jest',
-    testEnvironment: 'node',
-    moduleNameMapper: {
-      "^octokit$": "<rootDir>/node_modules/octokit/dist-bundle/index.js",
-      "^@github/dependency-submission-toolkit$": "<rootDir>/node_modules/@github/dependency-submission-toolkit/dist/index.js",
-    },
-    extensionsToTreatAsEsm: [".ts"],
-    transformIgnorePatterns: ["/node_modules/(?!(octokit|\\@github\\/dependency-submission-toolkit)/)"],  // Ensure octokit and @github/dependency-submission-toolkit are transformed
-    globals: {
-      "ts-jest": {
-        useESM: true,
-      },
-    },
-  };
+import babel from 'babel-jest';
+
+export default {
+  testEnvironment: 'node',
+  extensionsToTreatAsEsm: ['.ts'],
+  transform: {
+    '^.+\\.ts$': ['babel-jest', { configFile: './babel.config.js' }]
+  },
+  moduleNameMapper: {},
+  verbose: true,
+  collectCoverage: true,
+  coverageDirectory: 'coverage',
+  testMatch: ['**/*.test.ts'],
+  resolver: undefined,
+};