[Prettier Plugin] Automatically apply upgrade migrations

[aaronadamsCA]

I'd like the Prettier plugin to automatically run the same design system–driven migrations as the upgrade utility (#17831).

That way, if I have styles that could be written in a simpler way, Prettier can simplify them for me.

[philipp-spiess]

@aaronadamsCA We've been thinking about this but the issue right now is that these design-system driven migrations are relatively complex to compute and Prettier needs to be able to process the whole document in a very limited amount of time :/

[aaronadamsCA]

A fair point for sure!

I should have described a problem instead of jumping to a specific solution:

Big monorepo, many tailwind.css files, some of which depend on other tailwind.css files. Because Tailwind v4 is magic, I can prettier --write the whole monorepo or a single file and get the same result—every config resolves perfectly from any working directory. It's fast too.

Those upgrade migrations look great, but right now they're in a tool that does a lot of other stuff I don't want. If I had any way to run them on their own, I could hook that up to our monorepo tooling and run it as part of our checks.