A node that is loading weights looks identical to one that is computing:
progress_state carries only state/value/max, and load_models_gpu runs inside
the sampler, so the UI shows the sampler sitting at 0% while weights move.
Adds an optional activity field to the node progress state, reported through a
hook like the existing progress bar hook, and sets it to "loading" around the
VRAM load. The field is absent unless something sets it, so existing clients
are unaffected.
Vinh Trinh