Feature Request: Escape/Cancel Hook for Process Cleanup

Feature Request: Escape/Cancel Hook for Process Cleanup

Problem: When running scripts that spawn background processes, pressing Escape terminates the parent script but leaves child processes running without cleanup.

Example Scenario:

1. foo.sh launches a remote process and waits for response
2. User presses Escape to cancel
3. foo.sh terminates immediately
4. Remote process continues running (no cleanup signal sent)

Proposed Solution: Add a cancellation hook that triggers when Escape is pressed, allowing scripts to:

• Send termination signals to child processes
• Close network connections
• Clean up temporary resources
• Gracefully shut down before exiting

Implementation: Could be exposed as:

• Signal handler for SIGINT/SIGTERM
• Explicit cancel callback registration
• "onCancel" hook in the script lifecycle

This would ensure proper cleanup when users interrupt long-running operations.