- Added functionality to update the default LLM provider for users via a new endpoint in UserController.
- Introduced LlmProvider enum to manage available LLM options: Auto, Gemini, OpenAI, and Claude.
- Updated User and UserEntity models to include DefaultLlmProvider property.
- Enhanced database context and migrations to support the new LLM provider configuration.
- Integrated LLM services into the application bootstrap for dependency injection.
- Updated TypeScript API client to include methods for managing LLM providers and chat requests.
