Inversion-free adaptation of 'When to Lock Attention' (arxiv 2603.09657).
Track x0 prediction instability per step (relative step-change of the predicted
clean latent, video-masked = a cheap proxy for the paper's variance-of-x0
hallucination metric over a sliding window). High instability => the model is
still drifting => raise the shared kvlock_scale so BachVid holds the blessed
identity K/V harder; as x0 settles the multiplier relaxes toward base strength.
No DDIM inversion (LTXAV inverts poorly) — locks against the blessed K/V bank.
No-op unless a BachVid bank installed the shared scale list, so the two compose
cleanly. Wired into all three FunPack sampler loops after each model() call;
fully guarded, cannot break sampling. Tests cover capture/inject/scale + the
schedule's stable-vs-jumpy behavior and the no-bank no-op path.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
