Run them in headless [vitest browser
mode](https://vitest.dev/guide/browser/) in chromium and firefox.
Similar UX than current tests, it's about 5 times as slow (goes from 1s
to 5s on my machine), but definitely worth it as it removes all
happy-dom problems.
---------
Signed-off-by: silverwind <me@silverwind.io>
Some minor refactors, disable one obsolete lint rule, fix another. The
tribute type issue is not fully fixed and I'm pretty sure it must be an
error in their types.
Update eslint and all plugins. Many plugins still do not ship type
definitions so I had to add stubs. Also, I had to put a few typescript
error expectations because if some unknown error in the types.
`eslint-plugin-no-jquery` is disabled because it's not compatible with
eslint 9 flat config
(https://github.com/wikimedia/eslint-plugin-no-jquery/issues/311).
silverwind