Turn the v2 theme into a build-level standalone color system instead
of a runtime-scoped add-on. Reset Tailwind's default palette and keep
only transparent, black, white, and the Radix scales, so an app opts
into v2 by importing it in place of the v1 theme.
Drop the redundant [data-theme="v2"] block: isolation now comes from
the separate import, and the inline utilities never read those tokens.
Update the v2 color guide to describe build-level isolation.
Signed-off-by: Émile Ré <emile@probo.com>
f49d7846e4