feat: add Unity Editor support for remote MCP bridge connections

- Add AllowRemoteConnections setting to McpUnitySettings
- Update WebSocket server to bind to 0.0.0.0 when remote connections enabled
- Add UI checkbox in Unity Editor window for remote connection toggle
- Server automatically restarts when binding setting changes
- Defaults to localhost-only connections for security

Author: ichimi abunai

Editor/UnityBridge/McpUnityEditorWindow.cs

@@ -135,6 +135,19 @@ private void DrawServerTab()
 
             EditorGUILayout.Space();
 
+            // Allow remote connections toggle
+            bool allowRemoteConnections = EditorGUILayout.Toggle(new GUIContent("Allow Remote Connections", "Allow connections from remote MCP bridges. When disabled, only localhost connections are allowed (default)."), settings.AllowRemoteConnections);
+            if (allowRemoteConnections != settings.AllowRemoteConnections)
+            {
+                settings.AllowRemoteConnections = allowRemoteConnections;
+                settings.SaveSettings();
+                // Restart server to apply binding change
+                mcpUnityServer.StopServer();
+                mcpUnityServer.StartServer();
+            }
+            
+            EditorGUILayout.Space();
+            
             // Enable info logs toggle
             bool enableInfoLogs = EditorGUILayout.Toggle(new GUIContent("Enable Info Logs", "Show informational logs in the Unity console"), settings.EnableInfoLogs);
             if (enableInfoLogs != settings.EnableInfoLogs)

Editor/UnityBridge/McpUnityServer.cs

@@ -125,10 +125,11 @@ public void StartServer()
 
             try
             {
-                _webSocketServer = new WebSocketServer($"ws://localhost:{McpUnitySettings.Instance.Port}");
+                var host = McpUnitySettings.Instance.AllowRemoteConnections ? "0.0.0.0" : "localhost";
+                _webSocketServer = new WebSocketServer($"ws://{host}:{McpUnitySettings.Instance.Port}");
                 _webSocketServer.AddWebSocketService("/McpUnity", () => new McpUnitySocketHandler(this));
                 _webSocketServer.Start();
-                McpLogger.LogInfo($"WebSocket server started successfully on port {McpUnitySettings.Instance.Port}.");
+                McpLogger.LogInfo($"WebSocket server started successfully on {host}:{McpUnitySettings.Instance.Port}.");
             }
             catch (SocketException ex) when (ex.SocketErrorCode == SocketError.AddressAlreadyInUse)
             {

Editor/UnityBridge/McpUnitySettings.cs

@@ -36,6 +36,9 @@ public class McpUnitySettings
 
         [Tooltip("Optional: Full path to the npm executable (e.g., /Users/user/.asdf/shims/npm or C:\\path\\to\\npm.cmd). If not set, 'npm' from the system PATH will be used.")]
         public string NpmExecutablePath = string.Empty;
+        
+        [Tooltip("Allow connections from remote MCP bridges. When disabled, only localhost connections are allowed (default).")]
+        public bool AllowRemoteConnections = false;
 
         /// <summary>
         /// Singleton instance of settings