Keep a stopping machine listed until its shutdown returns, guard
against a second stop, and let the button say so and go quiet
instead of firing again.
A machine named after its template showed no subheading at all, and
with one Linux template the architecture is half the story. Both
panels now say template and architecture, whenever that adds to the
name.
Add a machine abstraction to LumaCore, with QEMU as its first
backend: templates mirroring frida-core's test guests, a QMP client,
and a display that maps QEMU's surface over D-Bus rather than
copying frames.
Leave readiness to the user: drive the guest, mark it ready, and come
back to that snapshot later. Keep the machine in the project, so
booting it again resumes where it was marked. Hand the stub to
addBareboneDevice, so it joins the picker beside the other devices.
Show the display while booting, and afterwards in a Machines panel,
which the side panel now models as an enum to share its slot.