vitest@4 breaks tests

[maxffarrell]

Svelte error: rune_outside_svelte
The $state rune is only available inside .svelte and .svelte.js/ts files
https://svelte.dev/e/rune_outside_svelte

[khromov]

The Vitest setup is a bit arcane to me since last I worked on it was the first day of the project 😅 I would guess we'd need to read the migration guide and perhaps adjust some config, although I don't see much immediate value of updating it?