Add Playwright e2e coverage and Node 20 pin

frontend/package.json

@@ -3,6 +3,9 @@
   "private": true,
   "version": "0.0.0",
   "type": "module",
+  "engines": {
+    "node": ">=20.19.0 <21 || >=22.12.0"
+  },
   "scripts": {
     "dev": "vite",
     "build": "tsc -b && vite build",
@@ -10,6 +13,10 @@
     "preview": "vite preview",
     "test": "vitest run",
     "test:watch": "vitest",
+    "test:e2e": "playwright test",
+    "test:e2e:headed": "playwright test --headed",
+    "test:e2e:ui": "playwright test --ui",
+    "test:e2e:debug": "playwright test --debug",
     "analyze": "vite-bundle-visualizer"
   },
   "dependencies": {
@@ -43,6 +50,7 @@
     "zustand": "^5.0.10"
   },
   "devDependencies": {
+    "@playwright/test": "^1.55.0",
     "@eslint/js": "^9.39.1",
     "@testing-library/jest-dom": "^6.9.1",
     "@testing-library/react": "^16.3.2",