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_

重現 GitHub Copilot CLI 1.0.43 中重複按下 CTRL+C 時的行為，並追蹤命令取消、工作階段結束及 "copilot fg" 提示的處理。完成的標準是：CTRL+C 只取消正在執行的命令，重複按下時提供退出確認而不是立即退出，CTRL+D 可以退出，並移除誤導性的恢復提示。

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