RH-W-15 validation

1. Pure-rational structural verifier: PASS
2. RH-W-13 center dependency verifier: PASS
3. Corrected RH-W-14 Lipschitz tail re-audit: PASS
4. Four W-15 corner LDL^T certificates: PASS
5. Tensor interpolation second-order remainder: PASS
6. Fixed prime-power chamber {2,3,4}: PASS
7. 60-digit selected-entry mpmath crosscheck: PASS
8. RH claim: False
