Five crates (tools, build, vcs, github, docker) each carried their own copy of killing a child and what it started, and only the tools installer killed the whole tree on Windows, so cancelling git, gh, docker or Maven/Gradle there left descendants running. ide-core now provides own_group, kill_tree and terminate_tree (process-group signals on Unix, taskkill /T /F on Windows) and the copies are removed. Unix behaviour is unchanged; the Windows path was not run locally.
Co-authored-by: bograh <69661398+bograh@users.noreply.github.com>