Ability to access the final vite config programmatically for use with Storybook/Histoire

[imadtg]

Is your feature request related to a problem? Please describe.
I love using slidev for interactive and complex visualizations, and i would love to be able to use storybook/histoire to prototype, test and document visualization components before using them in slides

Describe the solution you'd like
export a function that provides the final config, or atleast the internal one to be merged and the merging function to be able to call inside storybook/histoire configs.

Describe alternatives you've considered
of course the clear alternative is to recreate the config in code and override it in both the vite slidev config and the storybook/histoire config, or create slides for the stories that we want to document and test manually, but they all feel like hacks compared to proper stories...