Added ability to execute commands on multiple workers simultaneously:
- Added execution mode selector (Single/Multiple Workers)
- Multi-worker mode with checkbox list for worker selection
- Helper buttons: Select All, Online Only, Clear All
- Sequential execution across selected workers
- Results summary showing success/fail count per worker
- Updated command history to track multi-worker executions
- Terminal beep feedback based on overall success/failure
- Maintained backward compatibility with single worker mode
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
