feat: add Playwright E2E testing setup with POM and testids

- Install @playwright/test and Chromium browser
- Create playwright.config.ts with dev server integration
- Add data-testid attributes to LoginPage, DashboardPage, ServerCard, Sidebar
- Exclude tests-e2e from vitest config
- Create Page Object Models: LoginPage, DashboardPage
- Add 18 E2E tests: 6 login flow, 12 dashboard (happy, empty, error states)
- Add test:e2e and test:e2e:ui scripts to package.json

frontend/package.json

@@ -9,7 +9,9 @@
     "lint": "eslint .",
     "preview": "vite preview",
     "test": "vitest run",
-    "test:watch": "vitest"
+    "test:watch": "vitest",
+    "test:e2e": "playwright test",
+    "test:e2e:ui": "playwright test --ui"
   },
   "dependencies": {
     "@hookform/resolvers": "^5.2.2",
@@ -27,6 +29,7 @@
   },
   "devDependencies": {
     "@eslint/js": "^9.39.4",
+    "@playwright/test": "^1.59.1",
     "@testing-library/jest-dom": "^6.9.1",
     "@testing-library/react": "^16.3.2",
     "@testing-library/user-event": "^14.6.1",