Added ESLint as dev dependency

.github/workflows/eslint.yml

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+name: ESLint
+
+on: [push, pull_request]
+
+jobs:
+  eslint:
+    runs-on: ubuntu-latest
+    steps:
+
+      - name: Checkout repository code
+        uses: actions/checkout@v4
+
+      - name: Set up Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 21
+
+      - name: Install dependencies
+        run: npm ci # instead of install to ensure consistency and determinism in CI/CD workflow
+
+      - name: Run ESLint
+        run: npm run lint

.gitignore

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+node_modules/
+.eslintcache

eslint.config.mjs

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+import js from '@eslint/js';
+
+export default [
+    js.configs.recommended,
+    {
+        rules: {
+            'indent': 'off', 'no-unexpected-multiline': 'off', 'key-spacing': 'off', // allow whitespace anywhere
+            'quotes': ['error', 'single', { 'allowTemplateLiterals': true }], // enforce single quotes except backticks to avoid escaping quotes
+            'comma-dangle': ['error', 'never'], // enforce no trailing commas in arrays or objects
+            'no-async-promise-executor': 'off', // allow promise executor functions to be async (to accomodate await lines)
+            'no-constant-condition': 'off', // allow constant conditions
+            'no-empty': 'off', // allow empty blocks
+            'no-inner-declarations': 'off', // allow function declarations anywhere
+            'no-useless-escape': 'off', // allow all escape chars cause ESLint sucks at detecting truly useless ones
+            'no-unused-vars': ['error', { 'caughtErrors': 'none' }] // allow unused named args in catch blocks
+        },
+        languageOptions: { ecmaVersion: 2022, sourceType: 'script', globals: { chrome: 'readonly' }}
+    },
+    { files: ['**/*.mjs'], languageOptions: { sourceType: 'module' }}
+];