[Add] Universal modifier system, shop, inventory & persistence

Replace hardcoded BonusForOnes/MultiplierForSixes with data-driven
modifier system supporting 2 scopes (SelectedCategory, AnyCategoryClosed),
4 effect types, durability modes (Permanent, LimitedUses), and
configurable targets via ScriptableObject (ModifierData).

- Modifier domain: ModifierEnums, ModifierTarget, ModifierData,
  ModifierRuntime, ModifierEffect (dict-based strategy), ModifierPipeline
  (4-pass: cat-additive → cat-multiplicative → final-additive → final-multiplicative)
- ScoringSystem: replaced old modifier list with ModifierPipeline integration,
  added OnCategoryConfirmed event
- Shop MVC: ShopCatalog (SO), ShopModel, ShopView, ShopItemView, ShopController
- Inventory MVC: InventoryModel (activate/deactivate/sell/durability),
  InventoryView, InventorySlotView, InventoryController
- CurrencyBank: editor-adjustable balance with events
- Persistence: SaveData + SaveSystem (Newtonsoft JSON + PlayerPrefs)
- Editor: ModifierAssetCreator menu item to generate 6 example modifiers + catalog
- Tests: 6 test classes covering effects, pipeline, scoring, shop, inventory, save
- GameController: wired shop/inventory/save lifecycle
- GameInfoView: added currency display, shop/inventory toggle buttons

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

Assets/Scripts/Modifiers/ModifierRuntime.cs

@@ -0,0 +1,34 @@
+using System;
+
+[Serializable]
+public sealed class ModifierRuntime
+{
+    public string ModifierId;
+    public bool IsActive;
+    public int RemainingUses;
+
+    [NonSerialized] public ModifierData Data;
+
+    public bool IsExpired => Data != null &&
+                             Data.Durability == ModifierDurability.LimitedUses &&
+                             RemainingUses <= 0;
+
+    public void ConsumeUse()
+    {
+        if (Data == null) return;
+        if (Data.Durability != ModifierDurability.LimitedUses) return;
+
+        RemainingUses--;
+    }
+
+    public static ModifierRuntime Create(ModifierData data)
+    {
+        return new ModifierRuntime
+        {
+            ModifierId = data.Id,
+            IsActive = false,
+            RemainingUses = data.Durability == ModifierDurability.LimitedUses ? data.MaxUses : -1,
+            Data = data
+        };
+    }
+}