[Refactor] Add folder-based namespaces to all C# scripts

Wrap all 39 scripts and 6 test files in namespaces matching their folder
structure (e.g. Assets/Scripts/Dice/ → YachtDice.Dice). Add cross-namespace
using directives where types are referenced across modules. Set rootNamespace
in both .asmdef files (YachtDice, YachtDice.Tests).

Namespace mapping:
- YachtDice.Dice — Dice, DiceRoller
- YachtDice.Economy — CurrencyBank
- YachtDice.Game — GameManager, DiceManager, DebugGameInput
- YachtDice.Inventory — InventoryController/Model/SlotView/View
- YachtDice.Modifiers — ModifierData/Effect/Enums/Pipeline/Runtime/Target
- YachtDice.Persistence — SaveData, SaveSystem
- YachtDice.Scoring — CategoryScorer, ScoreResult, ScoringSystem, YachtCategory
- YachtDice.Shop — ShopCatalog/Controller/ItemView/Model/View
- YachtDice.UI — CategoryRowView, DicePanelView, GameController, GameInfoView, ScoreCardView
- YachtDice.Editor — ModifierAssetCreator
- YachtDice.Tests — all test files

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

Assets/Scripts/UI/CategoryRowView.cs

@@ -2,6 +2,10 @@ using System;
 using UnityEngine;
 using UnityEngine.UI;
 using TMPro;
+using YachtDice.Scoring;
+
+namespace YachtDice.UI
+{
 
 public sealed class CategoryRowView : MonoBehaviour
 {
@@ -87,3 +91,4 @@ public sealed class CategoryRowView : MonoBehaviour
         selectButton.onClick.RemoveListener(HandleClick);
     }
 }
+}

Assets/Scripts/UI/DicePanelView.cs

@@ -3,6 +3,9 @@ using UnityEngine;
 using UnityEngine.UI;
 using TMPro;
 
+namespace YachtDice.UI
+{
+
 public sealed class DicePanelView : MonoBehaviour
 {
     [Header("Dice Display")]
@@ -99,3 +102,4 @@ public sealed class DicePanelView : MonoBehaviour
         rollButton.onClick.RemoveAllListeners();
     }
 }
+}

Assets/Scripts/UI/GameController.cs

@@ -1,6 +1,16 @@
 using System;
 using System.Collections.Generic;
 using UnityEngine;
+using YachtDice.Game;
+using YachtDice.Scoring;
+using YachtDice.Economy;
+using YachtDice.Shop;
+using YachtDice.Inventory;
+using YachtDice.Persistence;
+using YachtDice.Modifiers;
+
+namespace YachtDice.UI
+{
 
 public sealed class GameController : MonoBehaviour
 {
@@ -345,3 +355,4 @@ public sealed class GameController : MonoBehaviour
         return total;
     }
 }
+}

Assets/Scripts/UI/GameInfoView.cs

@@ -3,6 +3,9 @@ using UnityEngine;
 using UnityEngine.UI;
 using TMPro;
 
+namespace YachtDice.UI
+{
+
 public sealed class GameInfoView : MonoBehaviour
 {
     [Header("Turn Info")]
@@ -67,3 +70,4 @@ public sealed class GameInfoView : MonoBehaviour
             inventoryButton.onClick.RemoveAllListeners();
     }
 }
+}

Assets/Scripts/UI/ScoreCardView.cs

@@ -2,6 +2,10 @@ using System;
 using System.Collections.Generic;
 using UnityEngine;
 using TMPro;
+using YachtDice.Scoring;
+
+namespace YachtDice.UI
+{
 
 public sealed class ScoreCardView : MonoBehaviour
 {
@@ -107,3 +111,4 @@ public sealed class ScoreCardView : MonoBehaviour
             categoryRows[i].OnCategorySelected -= HandleCategorySelected;
     }
 }
+}