* Add all missing libraries in the packages/apps.
* Add all missing Vitest imports to the tests.
* Add some missing exports to ui.
* Fix the admonition export.
* Fix various minor bugs.
* Migrate the ui package to use vitest.
The footnote link/anchor was incorrect because the getAnchor logic doesn't check if the component comes with its own id (which overrides the generated id), and the anchor must match the id. This is the case for footnote headings, which are auto-generated by remarkGfm.
Move useClients to the actual file instead of index files, so that (a) we don't
ship unnecessary client-side code and (b) we don't get the "can't dot into
client component from server" error when trying to use MDX in RSCs.
Ivan Vasilov