Rendering the Secure Keyboard Input overlay using
innerShadow() can strain the resources of the main
thread, leading to elevated CPU load and in some
cases extended disruptions to the main thread's
DispatchQueue that result in lag or frozen frames.
This change achieves the same animated visual
effect with ~35% lower CPU usage and resolves most
or all of the terminal rendering issues associated
with the overlay.
This only works on macOS 15 because it uses the new `pointerStyle` API.
I don't have the interest to backport this to older macOS versions but
I'm happy to accept a PR if someone else wants to do it.
