Make UI report when running in an unsupported browser

[rtertiaer]

Determine our minimum emcascript version necessary (we use structuredClone, used to use top level await, check here) and report to the user that their browser is unsupported and their experience is not guaranteed.

[SteveMicroNova]

This is on the 0.5.0 board but not the filtered 0.5.0 board Seems strange seeing as user-experience is part of the filtration model

EDIT: This is because of the -enhancement filter, ignore me Tho it's weird to exclude user experience things if they're also enhancements? I feel those two categories go hand in hand, squares and rectangles style.