test: add E2E tests covering full user journeys

- Create tests/e2e/full-flow.spec.ts with 5 E2E scenarios
- Test home page navigation and layout
- Test game creation via form
- Test metadata search functionality
- Test ROM-to-game linking workflow
- Test complete user journey: create → search → link → view
- Configure Playwright for multi-browser testing (chromium, firefox, webkit)
- Optimize playwright.config.ts for E2E stability
- Total: 15 tests (5 scenarios × 3 browsers)

playwright.config.ts

@@ -2,21 +2,27 @@ import { defineConfig, devices } from '@playwright/test';
 
 export default defineConfig({
   testDir: 'tests',
+  testMatch: '**/*.spec.ts',
   timeout: 30_000,
   expect: {
     timeout: 5000,
   },
-  fullyParallel: true,
-  reporter: 'list',
+  fullyParallel: false, // Set to false for E2E to avoid race conditions
+  reporter: [['list'], ['html']],
   use: {
+    baseURL: 'http://localhost:5173', // Frontend URL
     headless: true,
     viewport: { width: 1280, height: 720 },
-    actionTimeout: 0,
+    actionTimeout: 10_000,
     ignoreHTTPSErrors: true,
+    trace: 'on-first-retry',
   },
   projects: [
     { name: 'chromium', use: { ...devices['Desktop Chrome'] } },
     { name: 'firefox', use: { ...devices['Desktop Firefox'] } },
     { name: 'webkit', use: { ...devices['Desktop Safari'] } },
   ],
+
+  // Global timeout
+  globalTimeout: 60 * 60 * 1000, // 1 hour
 });