Provable-fairness verification round

This round's committed seed was d055a764eb34c2d5f35abd74dd710d8a19ce380a4a882fe51379ffe1f946bf56, revealing 2X_TO_5X as the winning band. Verify this yourself: fetch manifest.json and run scripts/verify_fairness.py against it. This proves the result matches what was committed before the round; it still assumes we drew the seed fairly and didn't grind the commitment.