- Implemented `ask_user` middleware to facilitate agent-initiated questions during research workflows.
- Created `AskUserWidget` for interactive user prompts, supporting both text and multiple choice questions.
- Enhanced `StreamEventEmitter` to handle `ask_user` interrupts and updated event handling in `stream_agent_events`.
- Added state management for pending `ask_user` events in `StreamState`.
- Developed validation for question structures and parsing for responses.
- Introduced unit tests covering middleware functionality, event handling, and widget behavior.
X-iZhang