- Replaced PKCE-based OAuth for xAI with device authorization flow for enhanced compatibility.
- Introduced cancelable OAuth sessions with server-side invalidation to prevent token persistence on flow interruption.
- Updated OAuth polling and session tracking to handle device flow specifics, such as `user_code` and extended timeouts.
- Refactored TUI OAuth model to track polling generations, distinguish device flow, and handle session cancellation gracefully.
- Extended test cases for device flow scenarios, stale session handling, and cancelation logic.
- Streamlined xAI device flow management in handler logic and improved error handling.