Task-vector graft: curriculum-DR constitutional midtraining applied post-SFT

merged = geodesic-research/nemotron-super-120b-cc-mt-replay-only-1b-200k-sft + 1.0 * (geodesic-research/nemotron-super-120b-cc-mt-curriculum-dr - geodesic-research/nemotron-super-120b-cc-mt-replay-only-1b)

All three source checkpoints are from the Constitutional Midtraining paper (arXiv:2607.26654, geodesic-research). This model tests whether the constitutional-midtraining weight delta (taken post-midtraining, replay cancelled via the control anchor) installs the same alignment behaviour when added to the control after its 200K SFT — i.e., whether the effect is portable content rather than midtraining placement. Built shard-wise in fp32, cast back to bf16; exact source revisions and delta norms in task_vector_report.json.