- Change from Flask to Quart imports for async compatibility
- Use async/await syntax for all route handlers
- Use @manager.route() decorator pattern (RAGFlow standard)
- Fix request.get_json() to use await
- Import login_required from api.apps instead of flask_login
- Import RetCode from common.constants instead of api.settings
This fixes the service startup issue in CI/CD where Flask imports
were incompatible with RAGFlow's Quart-based async architecture.