[Bug] stopOnAbort fails to detach abort event listeners after execution

[akramcodez]

Description

When training ends, the abort listener on AbortSignal is not actively detached. If the same signal instance is aborted later in the application lifecycle, subprocess.kill('SIGINT') might try to kill an already terminated or recycled PID.

Environment

• macOS version: macOS 14.0
• Apple Silicon: M2
• Node version: v22.0.0
• Python version: 3.12
• Nanotune version: 1.7.0

Steps to Reproduce

1. Run a training session with an AbortSignal.
2. Let the session complete successfully.
3. Abort the signal externally.

Expected Behavior

Nothing should happen, as the process is dead.

Actual Behavior

The listener fires and calls kill('SIGINT') on the closed child process.

Logs/Screenshots

N/A

Additional Context

• I have searched existing issues to ensure this is not a duplicate
• I can reproduce this issue consistently
• This issue occurs with the latest version of nanotune