Review follow-ups on the Windows skip:
- Most people who hit the boot loop launched Desktop from the Start menu and
never open a terminal. The in-app update also rebuilds the app: the
Windows shim waits for Desktop to exit, and the already-up-to-date path
still completes with desktop=True. The notice and updating.md now name
Update now in Settings -> About next to `hermes desktop`.
- cmd_gui took the skip's None as "no launchable app was found". A build
that fails raises instead of returning None, so None there only means the
skip, and `hermes desktop` now reopens the app that was kept.
Tests fold to the two invariants, each red when its half of the fix is
reverted: the stop spares its ancestor Desktop on every platform, and a
Windows packaged build under its own Desktop is skipped (now driven through
the real _desktop_ancestor_in with a fake process tree, instead of a stub).