dark-matter-quantum-sim v2.1: DM-003 erratum — bitstring extraction defect corrected (FAIL→PASS)

Erratum for DM-003-ibmq-v1. The original DM-003 IBM Quantum runner extracted the spin-flip probability from the wrong Qiskit bitstring ('10' = initial state instead of '01' = target state). The published FAIL verdict (99.6% error) is incorrect; the hardware actually produced a PASS (2.0% error, 98.0% flip probability vs analytic 100%). This deposit contains: (1) the erratum document, (2) the corrected runner, and (3) the corrected ProofRecord. The original ProofRecord is preserved unchanged in the repository. GitHub: ERRATUM_DM-003.md