signature fix for real this time

[Darkmajia]

FOR FUCKING REAL THIS TIME. turns out i was onto something with #1358 but i didn't connect the dots properly. the issue was that fonts were attempting to be validated server-side, but the server build doesnt actually contain any of the resources, so the check would fail every time and give the default font

to remedy this, the check is made clientside, displaying a default font if the font couldnt be validated via prototype. fonts are also registered through prototypes instead of raw paths because, to be honest, it was kind of dumb to do it that way to begin with. HOPEFULLY I DONT HAVE TO THINK ABOUT THIS SYSTEM EVER AGAIN

i would really like to have used ProtoId<FontPrototype> for fonts instead of treating them as raw strings, but there's an upstream todo for moving FontPrototype from robust client to shared, so.. upstream issue

Changelog
🆑

• fix: Signature fonts should, hopefully, well and truly, finally be fixed.

[kipdotnet]

Again, I dont have a way to actually test this so ill take your word for it