chore: fix up vitest configs and ci

[teemingc]

The test-kit CI jobs take more than 17 minutes each because it's several consecutive groups of tests. If one test fails, everything needs to be retried and that's another 17 minutes. Separating them into unit, dev, and build, might make it a little faster since they run in parallel and it also makes test retries less painful. This may take up more CI minutes but definitely less wall clock time.

This PR also tightens the Vitest workspace config so that it works with both the VS Code Vitest extension and the built-in one for Zed.

EDIT: it takes 10 minutes to complete everything now

[pkg-svelte-dev]

Install the latest version of @sveltejs/kit from 1c86eae:

pnpm add https://pkg.svelte.dev/@sveltejs/kit/c/1c86eaee36abbf151ddecfad2d3e7cf6c736dad1

Open in pkg.svelte.dev: https://pkg.svelte.dev/repos/kit/pr/16555

[svelte-docs-bot]

Preview: https://svelte-dev-git-preview-kit-16555-svelte.vercel.app/

[teemingc]

Vitest expects vitest.*.config.js filenames otherwise the extension throws

[elliott-with-the-longest-name-on-github]

thanks my guy

[elliott-with-the-longest-name-on-github]

Noticed this is draft but it looks done?

[teemingc]

Yeah there are a few vitest run scripts that still need to be fixed. It’s running all the unit tests rather just the ones in the directory

[changeset-bot]

⚠️ No Changeset found

Latest commit: 1c86eae

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR