Keystone I: The First Bearing

Bridge-Admitted Response Unification in Deep Origin Theory.This preprint presents Keystone I, a bounded technical result in Deep Origin Theory. It materializes a bridge-admitted response-unification layer under explicit ceilings and closed-scope discipline. The paper establishes the admissible common-response architecture, the parent-preserving route, and the publication-ready bounded result without claiming final cosmology, H(z), D_L(z), full unification, or terminal closure.Status of claims: this record is a technical preprint and priority timestamp for the bounded Keystone I result only. Cosmology remains held closed at this stage, and downstream routes are not claimed here as completed.