Monoscopic/untracked considerations for Model element

[zachernuk]

Now that some parties are considering Model outside of visionOS, the questions of whether/how to manage ideas like background transparency, film-back-shift scrolling, and FoV considerations become relevant.

It seems like there's validity to making FoV and background transparency adjustable, but consistency and simplicity would really push us toward approaches that retain as much similarity on a tracked vs. an untracked platform.

/facetoface