This PR adjusts the representations of `ColorScale`s to allow us to
remove an unsafe `From` impl when converting from the statically-defined
representation of the scale.
Release Notes:
- N/A
This PR reworks the theme definition in the `theme2` crate to be based
off of the new theme work that @iamnbutler has been working on.
We're still developing the new theme system, but it is complete enough
that we can now load the default theme and use it to theme the storybook
(albeit with some further refining of the color palette required).
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Co-authored-by: Nate Butler <iamnbutler@gmail.com>
Co-authored-by: Marshall Bowers <marshall@zed.dev>
