Code editor preview doesn't include CSS for dependencies of dependencies

Assigning for review to land the stop-gap solution, then we'll leave the issue open for the proper one.

Stop-gap solution done. 🚢

I tinkered a bit with the ?withDeps option and it doesn't really work because for published components the CSS is written to disk so we can't get a different version based on a url param.

I was thinking what about we add a new controller /xb/api/code-component/css-preview that takes a URL param for the imports we need.

So then in Preview.tsx we'd just hit `xb/api/code-components/css-preview?components[]=code&components[]=hero` where we're basically requesting all of the import names we parsed from the AST.

Then that controller can just include the CSS for each of them, including their deps.

#7: Would the new controller take care of returning the CSS for the dependencies (and their dependencies, recursively) of the import names we pass? I assume yes, otherwise we'd be back to why I chose the stop-gap solution where we would need to parse all dependencies recursively to be able to pass all component names.

Yes and it would be smart enough to know to load the autosave version if a draft existed