- Remove 'r' key handler that was causing hang on refresh
- Remove RefreshRequested event and check_refresh_request method
- Remove send_refresh_commands function and ZMQ command protocol
- Remove refresh_requested field from App struct
- Clean up status line text (refresh -> tick)
The refresh functionality was causing the dashboard to become unresponsive
when pressing 'r' key. This removes all refresh-related code to fix the issue.