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/_Game/Scripts/Network/NetworkLauncher.cs

@@ -0,0 +1,45 @@
+using UnityEngine;
+using Unity.Netcode;
+
+namespace Colosseum.Network
+{
+    /// <summary>
+    /// 네트워크 연결 관리 (Host/Client 시작)
+    /// </summary>
+    public class NetworkLauncher : MonoBehaviour
+    {
+        [Header("UI References")]
+        [SerializeField] private GameObject connectionUI;
+
+        private void Start()
+        {
+            // 게임 시작 시 UI 표시
+            if (connectionUI != null)
+                connectionUI.SetActive(true);
+        }
+
+        public void StartHost()
+        {
+            NetworkManager.Singleton.StartHost();
+            HideConnectionUI();
+        }
+
+        public void StartClient()
+        {
+            NetworkManager.Singleton.StartClient();
+            HideConnectionUI();
+        }
+
+        public void StartServer()
+        {
+            NetworkManager.Singleton.StartServer();
+            HideConnectionUI();
+        }
+
+        private void HideConnectionUI()
+        {
+            if (connectionUI != null)
+                connectionUI.SetActive(false);
+        }
+    }
+}