Add ESLint, Husky, lint-staged and CI workflow for format/lint enforcement

Co-authored-by: kalwalt <[email protected]>

Author: Copilot

.editorconfig

@@ -0,0 +1,8 @@
+root = true
+
+[*]
+end_of_line = lf
+insert_final_newline = true
+charset = utf-8
+indent_style = space
+indent_size = 2

.github/workflows/ci-format-lint.yml

@@ -0,0 +1,28 @@
+name: Format and Lint
+
+on:
+  pull_request:
+  push:
+    branches: [main, dev, 'copilot/**']
+
+jobs:
+  format-lint:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Use Node
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+          cache: npm
+
+      - name: Install
+        run: npm ci
+
+      - name: Prettier check
+        run: npm run format-check
+
+      - name: ESLint
+        run: npm run lint

.husky/pre-commit

@@ -0,0 +1,5 @@
+#!/usr/bin/env sh
+. "$(dirname -- "$0")/_/husky.sh"
+
+# Only format and lint what's staged (fast)
+npx lint-staged

eslint.config.js

@@ -0,0 +1,69 @@
+import js from '@eslint/js';
+import prettier from 'eslint-config-prettier';
+
+export default [
+  {
+    ignores: ['dist/', 'node_modules/', 'coverage/', 'types/'],
+  },
+  js.configs.recommended,
+  prettier,
+  {
+    languageOptions: {
+      ecmaVersion: 2022,
+      sourceType: 'module',
+      globals: {
+        // Browser globals
+        window: 'readonly',
+        document: 'readonly',
+        navigator: 'readonly',
+        console: 'readonly',
+        alert: 'readonly',
+        HTMLElement: 'readonly',
+        HTMLVideoElement: 'readonly',
+        HTMLCanvasElement: 'readonly',
+        Image: 'readonly',
+        ImageData: 'readonly',
+        fetch: 'readonly',
+        CustomEvent: 'readonly',
+        MediaStream: 'readonly',
+        performance: 'readonly',
+        screen: 'readonly',
+        location: 'readonly',
+        WebAssembly: 'readonly',
+        setTimeout: 'readonly',
+        clearTimeout: 'readonly',
+        setInterval: 'readonly',
+        clearInterval: 'readonly',
+        requestAnimationFrame: 'readonly',
+        cancelAnimationFrame: 'readonly',
+        // Node.js globals
+        process: 'readonly',
+        __dirname: 'readonly',
+        __filename: 'readonly',
+        require: 'readonly',
+        module: 'readonly',
+        exports: 'readonly',
+        // Testing globals (vitest)
+        describe: 'readonly',
+        test: 'readonly',
+        it: 'readonly',
+        expect: 'readonly',
+        beforeEach: 'readonly',
+        afterEach: 'readonly',
+        beforeAll: 'readonly',
+        afterAll: 'readonly',
+        vi: 'readonly',
+        // AR.js specific globals
+        ArToolkitContext: 'writable',
+        ArMarkerControls: 'writable',
+      },
+    },
+    rules: {
+      // Relax rules for existing codebase patterns
+      'no-empty': 'off',
+      'no-unused-vars': 'off',
+      'no-unused-private-class-members': 'off',
+      'no-redeclare': 'off',
+    },
+  },
+];