[Rename] Unify Die → Dice naming across the entire project

Standardize all class, interface, file, method, event, field, and variable
names from the inconsistent "Die" form to "Dice", matching the existing
DiceManager/DiceCatalog/DiceCollection convention.

Renamed files (7 + meta): IDie→IDice, DieInstance→DiceInstance,
DieDefinitionSO→DiceDefinitionSO, StandardDieSO→StandardDiceSO,
DieValueCondition→DiceValueCondition, AddPerDieEffect→AddPerDiceEffect,
MultiplyPerDieEffect→MultiplyPerDiceEffect.

Updated all 31 consumer and test files with matching reference changes.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Assets/Scripts/Modifiers/Core/ModifierContext.cs

@@ -16,7 +16,7 @@ namespace YachtDice.Modifiers.Core
         public float PostMultiplier = 1f;
 
         /// <summary>Абстрактные дайсы (основной API).</summary>
-        public IReadOnlyList<IDie> Dice;
+        public IReadOnlyList<IDice> Dice;
 
         /// <summary>Значения дайсов (обратная совместимость с существующими модификаторами).</summary>
         public int[] DiceValues;
@@ -55,7 +55,7 @@ namespace YachtDice.Modifiers.Core
 
         public static ModifierContext CreateForScoring(
             int baseScore,
-            IReadOnlyList<IDie> dice,
+            IReadOnlyList<IDice> dice,
             CategoryDefinition category,
             int currentRoll,
             int currentTurn,