CTRL+C is a bit too efficient - cancel current running command - not whole session

### Describe the bug

- stop prompting to use "copilot fg" when I accidentally exit copilot - it does not work. And please - try to find a
way to show "Are you sure you want to exit" when a ctrl+c is entered too many times - cancelling a command should not be
treated as an exit - please use CTRL+D for exit

### Affected version

GitHub Copilot CLI 1.0.43.

### Steps to reproduce the behavior

CTRL+C too many times

### Expected behavior

Just cancel the running command

Use CTRL+D for exit

Stop issuing prompt "copilot fg" to resume - it does nothing

### Additional context

_No response_

Reproduce the repeated CTRL+C behavior in GitHub Copilot CLI 1.0.43 and trace the command-cancellation, session-exit, and "copilot fg" prompt handling. Done means CTRL+C cancels only the running command, repeated presses provide an exit confirmation rather than exiting immediately, CTRL+D exits, and the misleading resume prompt is removed.

Written by the indexing model from the issue text.