To enable Google Sign-In, add either your Firebase Web App credentials or Google OAuth credentials to your .env file:
# In your .env file:FIREBASE_API_KEY=AIzaSy... FIREBASE_AUTH_DOMAIN=your-app.firebaseapp.com FIREBASE_PROJECT_ID=your-app FIREBASE_APP_ID=1:12345:web:... # Or standard Google OAuth:GOOGLE_CLIENT_ID=...apps.googleusercontent.com