[Refactor] Replace enum-driven modifier system with data-driven SO composition

Replace the entire static, enum-based modifier pipeline with a
composition-based, data-driven architecture using ScriptableObject
polymorphism. New modifiers can now be created by assembling SO building
blocks (Conditions + Effects + Behaviors) — no core code edits needed.

New architecture:
- Core/: TriggerType, ModifierPhase, ModifierContext, ICondition, IEffect
- Definition/: ModifierDefinitionSO, ModifierBehaviorSO, ConditionSO, EffectSO, ModifierCatalogSO
- Conditions/: DieValueCondition, CategoryCondition, MinScoreCondition, DiceCountCondition
- Effects/: AddFlat, AddPerDie, Multiply, MultiplyPerDie, PostMultiply, AddCurrency, ConsumeCharge
- Runtime/: ModifierInstance, ModifierRegistry (non-static service)
- Pipeline/: async ModifierPipeline with phase ordering, tracing, anti-recursion
- Editor/: ModifierDefinitionValidator with menu items
- Events/: GameEventBus (non-static typed dispatcher)
- DI/: GameLifetimeScope (VContainer composition root)

Deleted old system: ModifierData, ModifierEffect, ModifierEnums,
ModifierPipeline (static), ModifierRuntime, ModifierTarget, ShopCatalog,
ModifierAssetCreator.

Updated: ScoringSystem (VContainer + async), InventoryModel (delegates to
ModifierRegistry), ShopModel (uses ModifierDefinitionSO), GameController
(VContainer injection), SaveData (uses Runtime.ModifierSaveEntry), all
views/controllers, and all test files.

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

Assets/Scripts/Modifiers/Runtime/ModifierSaveData.cs

@@ -0,0 +1,22 @@
+using System;
+using System.Collections.Generic;
+
+namespace YachtDice.Modifiers.Runtime
+{
+    [Serializable]
+    public class ModifierSaveEntry
+    {
+        public string ModifierId;
+        public bool IsActive;
+        public int RemainingUses;
+        public int Stacks;
+        public List<CustomStateEntry> CustomState = new();
+    }
+
+    [Serializable]
+    public class CustomStateEntry
+    {
+        public string Key;
+        public float Value;
+    }
+}