네트워크 멀티플레이 환경 문제 수정

관련 문제가 다시 발생하면 이 커밋으로 돌아올 것

Assets/Scripts/ShortcutNetworkStarter.cs

@@ -0,0 +1,50 @@
+using UnityEngine;
+using UnityEngine.InputSystem;
+using Unity.Netcode;
+
+namespace Northbound
+{
+    public class ShortcutNetworkStarter : MonoBehaviour
+    {
+        [Header("Input Actions")]
+        [SerializeField] private InputActionReference startAsClientAction;
+        
+        private bool _isClientStarted = false;
+
+        private void Start()
+        {
+            if (startAsClientAction != null && startAsClientAction.action != null)
+            {
+                startAsClientAction.action.performed += StartAsClient;
+            }
+        }
+
+        private void OnDestroy()
+        {
+            if (startAsClientAction != null && startAsClientAction.action != null)
+            {
+                startAsClientAction.action.performed -= StartAsClient;
+            }
+        }
+
+        private void StartAsClient(InputAction.CallbackContext context)
+        {
+            if (NetworkManager.Singleton == null)
+            {
+                Debug.LogError("[ShortcutNetworkStarter] NetworkManager.Singleton이 null입니다!");
+                return;
+            }
+
+            if (NetworkManager.Singleton.IsClient)
+            {
+                Debug.Log("[ShortcutNetworkStarter] 이미 클라이언트 모드입니다.");
+                return;
+            }
+
+            _isClientStarted = true;
+
+            Debug.Log("[ShortcutNetworkStarter] 클라이언트 모드로 시작합니다...");
+            NetworkManager.Singleton.StartClient();
+        }
+    }
+}