Support typesafe CSF factories

[lishaduck]

Storybook 9 introduces "Typesafe CSF factories" (storybookjs/storybook#30112). While I acknowledge that Svelte CSF is different from normal CSF and already handles many of the issues that that RFC addresses, it would still be useful if the new defineMain, definePreview and preview.meta (as opposed to the current createMeta) chain was available both for consistency (I spent a lot of time looking for it) and typesafety.

[JReinhold]

I agree. 🙂 We have an internal RFC about exactly this that we're discussing, and hoping to publish soon.

Stay tuned!