Upgrade to Vitest 3

[HiDeoo]

This PR updates the Vitest version used in the monorepo to version 3.0.1 and unpins us from the 2.1.6 version.

• Changelog
• Migration guide

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Latest commit: f2594cf

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.

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Lighthouse	1 paths audited Performance: 100 (no change from production) Accessibility: 100 (no change from production) Best Practices: 100 (no change from production) SEO: 100 (no change from production) PWA: - View the detailed breakdown and full score reports

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[delucis]

Thanks @HiDeoo! Lovely painless upgrade ✨