iOS apps capped at 60 fps

## Bevy version

0.16

If your bug is rendering-related, copy the adapter info that appears when you run Bevy.

```ignore
WARN bevy_winit::winit_windows: Can't select current monitor on window creation or cannot find current monitor!
WARN bevy_diagnostic::system_information_diagnostics_plugin::internal: This platform and/or configuration is not supported!
```

## What you did

I ran my game in iOS.

## What went wrong

My monitor supports 120hz, and the phone has plenty of CPU headroom, but the framerate is software locked to 60fps.

## Additional information

iOS 18.4 on iPhone 14 Pro Max (real device)

Start by reproducing the issue on iOS 18.4 using an iPhone 14 Pro Max and inspect the iOS window and frame-rate path. Confirm the cause of the 60 FPS cap and verify that a capable 120 Hz device can run above 60 FPS without regressing normal iOS behavior.

Written by the indexing model from the issue text.