- Implemented UpdateAssistant method in Mongo, Redis, and Xun stores to allow partial updates of assistant fields.
- Updated Store interface to include the new UpdateAssistant method, enhancing the flexibility of assistant management.
- Added comprehensive tests for UpdateAssistant functionality, covering various scenarios including single and multiple field updates, JSON field handling, and error cases.
- Updated API routes to support PUT requests for updating assistants, ensuring proper permission checks and response handling.
