Bug Description

NullReferenceException occurs in MCPForUnityEditorWindow.ScheduleHealthCheck() when the window is closed but delayed callback still executes.

Stack Trace

NullReferenceException: Object reference not set to an instance of an object
MCPForUnity.Editor.Windows.MCPForUnityEditorWindow.<ScheduleHealthCheck>b__12_0 () (at ./Library/PackageCache/com.coplaydev.unity-mcp@81ef4be7614d/Editor/Windows/MCPForUnityEditorWindow.cs:170)

Problem

Line 170 uses await connectionSection?.VerifyBridgeConnectionAsync();

The null-conditional operator ?. returns null, but await null throws NullReferenceException.

Suggested Fix

private void ScheduleHealthCheck()
{
    EditorApplication.delayCall += async () =>
    {
        if (this == null || connectionSection == null)
        {
            return;
        }
        await connectionSection.VerifyBridgeConnectionAsync();
    };
}

Explicit null check before awaiting prevents the exception.

Environment

• Unity Version: 6.2 (6000.2.12f1)
• Package Version: com.coplaydev.unity-mcp@81ef4be7614d