AV (actor) re-warm-started from kitft/nla-qwen2.5-7b-L20-av on Sonnet-4.6 matryoshka data in the
v2 LIST format (no wrapper, never-train-EOS). Untruncated AV; the AR is item-truncated.
Global batch 256, lr 2e-5->2e-6 cosine, warmup 50, 1 epoch, injection_scale 150.
