Fix Django migration issues and add missing URLs

- Create missing templates app urls.py
- Fix REST_FRAMEWORK pagination settings
- Add DEFAULT_AUTO_FIELD configuration
- Create migration files for all apps
- Fix auto-generated model warnings
- Verify database setup with test project

backend/poker_api/settings.py

@@ -61,6 +61,8 @@ TIME_ZONE = 'Asia/Shanghai'
 USE_I18N = True
 USE_TZ = True
 
+DEFAULT_AUTO_FIELD = 'django.db.models.BigAutoField'
+
 STATIC_URL = 'static/'
 
 MEDIA_URL = '/media/'
@@ -74,6 +76,6 @@ CORS_ALLOWED_ORIGINS = [
 CORS_ALLOW_CREDENTIALS = True
 
 REST_FRAMEWORK = {
-    'DEFAULT_PAGINATION': 'rest_framework.pagination.PageNumberPagination',
+    'DEFAULT_PAGINATION_CLASS': 'rest_framework.pagination.PageNumberPagination',
     'PAGE_SIZE': 20,
 }