feat: 멀티플레이어 네트워크 동기화 구현

- 로비 씬 추가 및 LobbyManager/LobbyUI/LobbySceneBuilder 구현
- NetworkPrefabsList로 플레이어 프리팹 등록 (PlayerPrefab 자동스폰 비활성화)
- PlayerMovement 서버 권한 이동 아키텍처로 전환
  - NetworkVariable<Vector2>로 클라이언트 입력 → 서버 전달
  - 점프 JumpRequestRpc로 서버 검증 후 실행
- 보스 프리팹에 NetworkTransform/NetworkAnimator 추가 (서버 권한)
- SkillController를 NetworkBehaviour로 전환
  - PlaySkillClipClientRpc로 클립 override + 재생 원자적 동기화
  - OnEffect/OnSkillEnd 클라이언트 실행 차단
- WeaponEquipment 클라이언트 무기 시각화 동기화 수정
  - registeredWeapons 인덱스 기반 NetworkVariable 동기화
  - SpawnWeaponVisualsLocal로 클라이언트 무기 생성
  - 중복 Instantiate 버그 수정

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

Assets/_Game/Scripts/Network/LobbyManager.cs

@@ -0,0 +1,147 @@
+using System;
+using Unity.Collections;
+using Unity.Netcode;
+using Unity.Netcode.Transports.UTP;
+using UnityEngine;
+using UnityEngine.SceneManagement;
+
+namespace Colosseum.Network
+{
+    /// <summary>
+    /// 로비 상태 관리. NetworkBehaviour로 플레이어 목록을 모든 클라이언트에 동기화.
+    /// NetworkManager가 있는 오브젝트와 별개로 배치하거나 NetworkObject 컴포넌트 필요.
+    /// </summary>
+    public class LobbyManager : NetworkBehaviour
+    {
+        public static LobbyManager Instance { get; private set; }
+
+        [Header("Game Scene")]
+        [SerializeField] private string gameSceneName = "Test";
+
+        // 모든 클라이언트에 동기화되는 플레이어 목록
+        private NetworkList<LobbyPlayerData> _players;
+
+        public event Action OnPlayersChanged;
+
+        // ─── 초기화 ───────────────────────────────────────────────
+        private void Awake()
+        {
+            if (Instance != null && Instance != this)
+            {
+                Destroy(gameObject);
+                return;
+            }
+            Instance = this;
+
+            _players = new NetworkList<LobbyPlayerData>();
+        }
+
+        public override void OnNetworkSpawn()
+        {
+            _players.OnListChanged += _ => OnPlayersChanged?.Invoke();
+
+            if (IsServer)
+            {
+                NetworkManager.Singleton.OnClientConnectedCallback += OnClientConnected;
+                NetworkManager.Singleton.OnClientDisconnectCallback += OnClientDisconnected;
+
+                // 호스트 자신 추가
+                AddPlayer(NetworkManager.Singleton.LocalClientId);
+            }
+        }
+
+        public override void OnNetworkDespawn()
+        {
+            if (IsServer)
+            {
+                NetworkManager.Singleton.OnClientConnectedCallback -= OnClientConnected;
+                NetworkManager.Singleton.OnClientDisconnectCallback -= OnClientDisconnected;
+            }
+        }
+
+        // ─── 연결 제어 (클라이언트에서 호출) ─────────────────────
+        /// <summary>호스트 시작</summary>
+        public void StartHost(string ip, ushort port)
+        {
+            SetTransport(ip, port);
+            NetworkManager.Singleton.StartHost();
+        }
+
+        /// <summary>클라이언트로 접속</summary>
+        public void StartClient(string ip, ushort port)
+        {
+            SetTransport(ip, port);
+            NetworkManager.Singleton.StartClient();
+        }
+
+        public void Disconnect()
+        {
+            NetworkManager.Singleton?.Shutdown();
+        }
+
+        // ─── 플레이어 목록 ────────────────────────────────────────
+        public int PlayerCount => _players.Count;
+
+        public LobbyPlayerData GetPlayer(int index) => _players[index];
+
+        private void OnClientConnected(ulong clientId)
+        {
+            AddPlayer(clientId);
+        }
+
+        private void OnClientDisconnected(ulong clientId)
+        {
+            for (int i = 0; i < _players.Count; i++)
+            {
+                if (_players[i].ClientId == clientId)
+                {
+                    _players.RemoveAt(i);
+                    return;
+                }
+            }
+        }
+
+        private void AddPlayer(ulong clientId)
+        {
+            _players.Add(new LobbyPlayerData
+            {
+                ClientId = clientId,
+                PlayerName = new FixedString32Bytes($"Player {clientId}"),
+                IsReady = false
+            });
+        }
+
+        // ─── 준비 상태 ────────────────────────────────────────────
+        [Rpc(SendTo.Server)]
+        public void SetReadyRpc(bool isReady, RpcParams rpcParams = default)
+        {
+            ulong clientId = rpcParams.Receive.SenderClientId;
+            for (int i = 0; i < _players.Count; i++)
+            {
+                if (_players[i].ClientId == clientId)
+                {
+                    var data = _players[i];
+                    data.IsReady = isReady;
+                    _players[i] = data;
+                    return;
+                }
+            }
+        }
+
+        // ─── 게임 시작 ────────────────────────────────────────────
+        /// <summary>호스트만 호출 가능. 모든 플레이어가 준비되어야 활성화 권장.</summary>
+        public void StartGame()
+        {
+            if (!IsHost) return;
+            NetworkManager.Singleton.SceneManager.LoadScene(gameSceneName, LoadSceneMode.Single);
+        }
+
+        // ─── 유틸 ─────────────────────────────────────────────────
+        private void SetTransport(string ip, ushort port)
+        {
+            var transport = NetworkManager.Singleton?.GetComponent<UnityTransport>();
+            if (transport != null)
+                transport.SetConnectionData(ip, port);
+        }
+    }
+}

Assets/_Game/Scripts/Network/LobbyManager.cs.meta

@@ -0,0 +1,2 @@
+fileFormatVersion: 2
+guid: 8db7d99e81050fd4d8768e2fa31483a0

Assets/_Game/Scripts/Network/LobbyPlayerData.cs

@@ -0,0 +1,24 @@
+using Unity.Collections;
+using Unity.Netcode;
+
+namespace Colosseum.Network
+{
+    public struct LobbyPlayerData : INetworkSerializable, System.IEquatable<LobbyPlayerData>
+    {
+        public ulong ClientId;
+        public FixedString32Bytes PlayerName;
+        public bool IsReady;
+
+        public void NetworkSerialize<T>(BufferSerializer<T> serializer) where T : IReaderWriter
+        {
+            serializer.SerializeValue(ref ClientId);
+            serializer.SerializeValue(ref PlayerName);
+            serializer.SerializeValue(ref IsReady);
+        }
+
+        public bool Equals(LobbyPlayerData other) =>
+            ClientId == other.ClientId &&
+            PlayerName == other.PlayerName &&
+            IsReady == other.IsReady;
+    }
+}

Assets/_Game/Scripts/Network/LobbyPlayerData.cs.meta

@@ -0,0 +1,2 @@
+fileFormatVersion: 2
+guid: b07f5fad09b348b4387a5824c72f802f