Tracking issue: paper prototypes for editor-ready UI

As part of our UI overhaul (#254), we should be sure that we can comfortably produce both common and complex user interfaces. For the most part, these should be mocked out with whatever final solution we pick, and are considered "done" when a pseudocode implementation has been completed and does not have any serious implementation challenges. This is closely related to #1953, and we should try to ensure that all widgets required here are representable on that issue.

This is the current list of UI examples that we're targeting, focusing on diverse and complex examples:

- [ ] To-do list: state tracking, text entry, keyboard / mouse / joystick navigation
- [ ] [Oblivion spells UI](https://discord.com/channels/691052431525675048/743663673393938453/834254068741439489): complex nested UIs, tabular layouts
- [ ] Warcraft 3 building selection: many copies of related UI elements
- [ ] Basic editor GUI: dropdown menus, file selections, canvases, complex layouts
- [ ] MOBA controls: cooldowns, tight game-state integration, triggered effects
- [ ] Mini + full map: handling non-discrete interactions, automatically rendered UI-like elements
- [ ] Immersive VR information display: UI without a UI camera, 3D UI elements
- [ ] Hearthstone: animated UI, dynamic layouts, complex interactions, mobile vs. desktop
- [ ] Node graph: graphs, dynamic drawing, complex nonstandard layout

If you have other ideas for examples, please comment below with the unique challenges it will provide. We should keep this list reasonably short and diverse to limit the scope of this issue <3