Error toast after deleting sessions. - Failed to delete session: git ["fsmonitor--daemon", "stop"] failed: fatal: fsmonitor--daemon is not running

I haven't been able to figure out why this is happening but I often see the following error after deleting a session from the UI.

```
Delete failed
Failed to delete session: git ["fsmonitor--daemon", "stop"] failed: fatal: fsmonitor--daemon is not running
```

Start by reproducing session deletion in the GitHub Copilot app and trace the cleanup path that invokes Git fsmonitor. Confirm whether the error occurs when fsmonitor--daemon is not running, then verify that deleting a session succeeds without showing an erroneous failure toast.

索引モデルが issue の本文から書いたものです。