chore: Assets 디렉토리 구조 정리 및 네이밍 컨벤션 적용

- Assets/_Game/ 하위로 게임 에셋 통합
- External/ 패키지 벤더별 분류 (Synty, Animations, UI)
- 에셋 네이밍 컨벤션 확립 및 적용
  (Data_Skill_, Data_SkillEffect_, Prefab_, Anim_, Model_, BT_ 등)
- pre-commit hook으로 네이밍 컨벤션 자동 검사 추가
- RESTRUCTURE_CHECKLIST.md 작성

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

Assets/External/Models/SidekickCharacters/Scripts/Runtime/Serialization/SerializedCharacter.cs

@@ -0,0 +1,27 @@
+// Copyright (c) 2024 Synty Studios Limited. All rights reserved.
+//
+// Use of this software is subject to the terms and conditions of the Synty Studios End User Licence Agreement (EULA)
+// available at: https://syntystore.com/pages/end-user-licence-agreement
+//
+// For additional details, see the LICENSE.MD file bundled with this software.
+
+using System;
+using System.Collections.Generic;
+
+namespace Synty.SidekickCharacters.Serialization
+{
+    [Serializable]
+    public class SerializedCharacter
+    {
+        public string Name { get; set; }
+        public int Species { get; set; }
+        public List<SerializedPart> Parts { get; set; }
+        public SerializedColorSet ColorSet { get; set; }
+        public List<SerializedColorRow> ColorRows { get; set; }
+        public SerializedBlendShapeValues BlendShapes { get; set; } = new SerializedBlendShapeValues();
+
+        public SerializedCharacter()
+        {
+        }
+    }
+}