Three corrections that change the conclusions

cost is not unrestricted forcing cost. The fine-graining construction for $(1/3,2/3)$ uses four qubits. Nevertheless, I's permutation-symmetric three-qubit witness anchors the same diagonal law using a different construction I (label prop:three). Consequently, four-qubit optimality within the fine-graining family does not establish a four-qubit unrestricted forcing threshold.

equality is not diagonal faithfulness. The registered record equation compares classical observations of two typed programs. Diagonal faithfulness is a condition on an unknown conditional residual state. They are related in the Born characterization, but they are not identical definitions. The conditional rigidity theorem below states diagonal faithfulness separately.

finite probe is not a quantified theorem. A finite collection of successful tests does not establish admissibility over every state, gate, continuation, and record instance. Conversely, one exact failed instance can reject a proposed strategy. The computational appendix respects this asymmetry.