Verify any Duel Castle Roulette spin. 48-segment live wheel: HMAC-SHA256(serverSeed, `${randomness}:0`) → first 4 bytes mod 48 = landing sector. Drand-beacon randomness is committed pre-round (no client seed or nonce).
Duel commits to a drand beacon round before the game starts. The revealed randomnesshex value goes here — it's decoded as UTF-8 and used as the HMAC message instead of a client seed + nonce.
randomness
