One node per capability and no mode dropdown, because a mode widget spanning two
sampling paths is a mistake this line has already paid for. Shared plumbing sits
at module scope so a second node cannot drift from this one.
Built on ComfyUI core alone — no second pack to install, which is the whole
premise. Core's own fl2va node supplies the conditioning and keyframes; the
sampling and the two decodes mirror core's SamplerCustomAdvanced, VAEDecode and
vae_decode_audio, and say so where they do, so they can be diffed against the
source rather than trusted.
What it refuses to offer: sampler, scheduler, cfg, sigma shift, negative prompt.
What it guards: the checkpoint family (fl2va vs ref2va, read out of the workflow
because nothing in the MODEL object carries the filename), the canvas — core does
NOT round the output canvas on this path, so the menu is the only guard — and
both frames' fitting, which core does asymmetrically and silently.
66 offline checks in tests/test_offline.py, no pytest and no GPU needed. They
caught the canvas claim above, which an earlier draft had backwards.
