Every case now gets a -qmp unix socket (additive; no case notices). A
minimal client does the capabilities handshake and executes one command;
the per-case qmp_after hook sends it N seconds after boot, retrying until
the guest's socket is up. A case with a hook configured cannot pass until
the hook delivered — and the smoke case now carries a harmless
query-status hook, so the channel is proven end to end on every run.
This is how the power scenarios inject the real ACPI power-button event
(system_powerdown) in M21.1 and M21.3.
Daniel Samson