[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/Shop/ShopCatalog.cs

@@ -0,0 +1,20 @@
+using System.Collections.Generic;
+using UnityEngine;
+
+[CreateAssetMenu(fileName = "ShopCatalog", menuName = "YachtDice/Shop Catalog")]
+public sealed class ShopCatalog : ScriptableObject
+{
+    [SerializeField] private List<ModifierData> availableModifiers = new();
+
+    public IReadOnlyList<ModifierData> AvailableModifiers => availableModifiers;
+
+    public ModifierData FindById(string id)
+    {
+        for (int i = 0; i < availableModifiers.Count; i++)
+        {
+            if (availableModifiers[i] != null && availableModifiers[i].Id == id)
+                return availableModifiers[i];
+        }
+        return null;
+    }
+}