A Vulkan/HIP card's type and size come from the installed engine's own device probe, but
quickstart priced its pick before installing that engine, so a fresh AMD/Intel machine was sized
from system RAM and committed to the wrong download (live: an empty store picked the 35B-A3B
from a 50 GiB RAM budget; with the engine installed the same card picks the 27B).
The job now re-picks right after the engine install, before any bytes are committed, and updates
the job's target/model_id, which is what Desktop renders. The POST contract is unchanged.