[BUG] background tasks are not properly killed and cleared up natively on Windows (powershell)

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

When Claude Code cli launches a background task it's correctly shown up in the /bashes menu. But when the task is killed the actual process is still running on the OS.

What Should Happen?

When claude code quits/kills the process it should be properly killed and do not continue running and show up in Task Manager.

Error Messages/Logs

Steps to Reproduce

Start claude code, ask it to run a long running process in a background (for ex. npm run dev or something similar). The process will start. Try killing the process via /bashes - cc will display the process is killed but the process in fact will still be running and will be visible in Task Manager. Same happens when claude code quits via /quit slash command. Background processes launched by CC become orphans.

Claude Model

Other

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

2.0.5 (Claude Code)

Platform

Other

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

Using PowerShell Core