Port UI to Vide

Closes #40 As mentioned in the issue, switching to Vide drastically reduces the package size and should make it easier to support Luau (see #27). Changes: - General refactor/clean-up of UI code, though some improvements can still be made here. - Switched to Charm for state management as it's a more lightweight solution than Reflex, its approach to state management also suits this project better. -