Fixed the interrupt mechanism to show "[Interrupted by user]" message when ESC is pressed:
- Removed duplicate UI cleanup from ESC key handler that interfered with event processing
- Added centralized interrupted event emission in exception handler when abort signal is detected
- Removed duplicate event emissions from API call methods to prevent multiple messages
- Added abort signal support to preflight reasoning check for proper cancellation
- Simplified abort detection to only check signal state, not error messages
1d9b77298c