chore: use preview mode for tests in CI

Author: xmatthias

playwright.config.ts

@@ -73,7 +73,7 @@ export default defineConfig({
 
   /* Run your local dev server before starting the tests */
   webServer: {
-    command: 'pnpm run dev',
+    command: !process.env.CI ? 'pnpm run dev' : 'pnpm run preview --port 3000',
     url: 'http://localhost:3000',
     reuseExistingServer: !process.env.CI,
   },