Use useSyncExternalStore for useWindowDimensions hook instead of useState

[lewiscasewell]

Summary:

• Uses React 18’s recommended way to subscribe to external stores (useSyncExternalStore). So it is centralised vs creating separate state instances for each hook call.
• Optimised for concurrent rendering.
• Uses startTransition(), making updates low priority, so UI stays responsive. Which works well when the window is resized rapidly - e.g. in web

Changelog:

[GENERAL] [CHANGED] - Use useSyncExternalStore for useWindowDimensions hook instead of useState

Test Plan:

interface is identical to before so

const window = useWindowDimensions();