chore: migrate from Jest to Vitest

[nickserv]

What: migrate from Jest to Vitest

Why: Vitest is faster than Jest, compatible with most Jest APIs, and has better compatibility with Vite

How: migrate from Jest to Vitest

Checklist:

• Tests
• Ready to be merged
  

Notes:

1. I’m a little confused as to why there are two Vite configs (a main one which imports an inline one from scripts) and whether I edited the right one. Could you please explain?
2. The commit hook for Vitest is stalling locally on my machine. I'm not sure why, and since I have a slower machine and I don't personally care about running commit hooks, I'm skipping them for now. If you want I can attempt to fix this or preferably remove the commit hook later when I have more time and energy.

[smeijer]

Thanks! I'll take a look soon. Re the multiple configs, the one inside scripts is to build the chrome extension. You can ignore that. The site and tests can use the one in the root.

Re commit hook, it's fine if that gets disabled. But tests should be able to run on dev machines. Even on slower ones, so that developers don't rely on ci only. Remember, actions won't automatically run for first time contributors.