Probes wsl.exe -d <distro> -- pgrep -x claude before flagging a WSL pane
idle, with a 3s per-distro cache on the Rust side. If claude is running
anywhere in the distro, all panes in that distro stay out of the idle set
(per-pane granularity is out of scope — PIDs aren't observable from
Windows). PowerShell + SSH panes skip the probe and keep the legacy
always-notify behaviour.
