Ref T4100. Overall:
- Use token background color to communicate token type (blue = object, yellow = function, grey = disabled/closed, red = invalid).
- Use token icon color to make color choices consistent (specifically, use project icon colors in project tokens).
- For functions, use token icon to communicate function result type (e.g., viewer() has a user icon; members(...) has a group icon), since we don't need the icon to indicate "this is a function" anymore.