QHMB-01 v1.0: Quantum History Metric Bench Test - Source-Only Validation of the Scalar Process-History Variable D_H

QHMB-01 v1.0 is the consolidated source-only metric-qualification protocol for determining whether the scalar process-history variable D_H can function as a stable, reproducible, portable, and quantitatively meaningful experimental coordinate for MST-EXP-01. It integrates the conceptual architecture of QHMB-01 v0.3 with an executable preregistration layer specifying development/validation separation, synthetic ground-truth benchmarking, uncertainty calibration, family-level holdout, dynamic-range qualification, formal equivalence logic, adversarial reference and reconstruction challenges, lockout rules, and explicit PASS / ORDINAL-ONLY / NO-GO decisions. The central question is not whether D_H uniquely reconstructs a full process tensor. It does not. The question is whether deliberate scalar compression can remain scientifically useful by producing stable equivalence classes and prospective predictions. Particular attention is given to process pairs for which D_H(A) ≈ D_H(B) while the underlying process tensors remain demonstrably distinct. These 'metric collisions' are preserved as future gravity falsification pairs because the scalar MST-EXP-01 law predicts equal response for equal D_H under matched experimental conditions. QHMB-01 therefore acts as a qualification gate. If the selected metric is unstable, strongly dependent on arbitrary reconstruction choices, nonportable, or catastrophically sensitive to time discretization or intervention set, it does not advance. If it is stable enough to support reproducible predictions, scalar D_H earns the right to enter MST-EXP-01 as a deliberately incomplete but testable history coordinate. Keywords: process tensor; quantum history; process divergence; transmon; metric qualification; experimental metrology; MST-EXP-01; falsifiability.