dark-matter-quantum-sim: Preregistered Toy Dark Matter Hamiltonian Simulation — Classical + IBM Quantum Hardware Results

Preregistered, ProofRecord-governed quantum simulation of three toy dark matter candidate Hamiltonians (axion, sterile neutrino, WIMP exchange), run on both exact classical simulation and IBM Quantum hardware (ibm_marrakesh, 156-qubit Heron r2). Classical layer (2026-08-01): DM-001 FAIL (honest wrong prior), DM-002 PASS, DM-003 PASS. IBM Quantum hardware layer (2026-08-13, ibm_marrakesh): DM-001 HOLD (single snapshot), DM-002 PASS (4.6% error within 10% threshold), DM-003 FAIL (hardware noise prevents exchange coupling). Three of six verdicts are negative (FAIL or HOLD). All published per the RF preregistration covenant. Every result carries a self-binding SHA-256 ProofRecord. Honest scope: toy Hamiltonian simulations only; not detection of real dark matter. Repository: github.com/derekhone/dark-matter-quantum-sim