Add first draft of new wide-gamut color palette (#14693)

This PR updates all of the colors in our default theme to use OKLCH
instead of RGB and increases the overall chroma to take advantage of the
wider color gamut.

Just a first draft based on @danhollick's initial work — expecting these
will be further refined before a stable release as we continue to test
them.

<img width="628" alt="image"
src="https://github.com/user-attachments/assets/2de1bfca-fddd-47f9-b609-39f26abdee41">

---------

Co-authored-by: Adam Wathan <[email protected]>

Author: adamwathan

CHANGELOG.md

@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+- Add first draft of new wide-gamut color palette ([#14693](https://github.com/tailwindlabs/tailwindcss/pull/14693))
 - _Upgrade (experimental)_: Migrate `theme(…)` calls in classes to `var(…)` or to the modern `theme(…)` syntax ([#14664](https://github.com/tailwindlabs/tailwindcss/pull/14664))
 
 ### Fixed