expose macOS's native window cascading API (cascadeTopLeft(from:))

[aaadotpm]

Is your feature request related to a problem? Please describe.

I have multiple windows in my app, and I would like to use macOSs default behaviour for positioning windows.

Describe the solution you'd like

Expose cascadeTopLeft(from:) so we can use it from window := app.Window.NewWithOptions(application.WebviewWindowOptions{}) or window.SetPosition() 🙏

Describe alternatives you've considered

This does the trick for now, setting the cascadeOffset to 32, seems to be about right for macOS Tahoe, but I suspect it's smaller for earlier versions of macOS.

// Apply cascade offset for subsequent windows
if windowCount > 0 {
  // Get current position (first window will be centered by OS)
  // Then offset based on window count
  offset := windowCount * cascadeOffset
  // Position relative to top-left, accounting for menubar
  window.SetRelativePosition(100+offset, 100+offset)
}
windowCount++

Additional context

No response