Implements the core game loop for Yacht dice: 5-dice rolling with
lock/unlock, 3 rolls per turn, 13 standard scoring categories, and
an extensible ScriptableObject-based modifier system that applies
additive then multiplicative bonuses (chips+mult pattern).
Includes two test modifiers: BonusForOnes (+10 per 1) and
MultiplierForSixes (x6 per 6).
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
