Default export for modular styles

[wmertens]

V-E imports the generated CSS as .css files. I changed the plugin so that if there's a default export, it gets replaced with the generated CSS and no import is added.

This is great for Qwik, so that a style is only added to the HTML if it is used.

Is this good for a standard feature?

https://github.com/wmertens/styled-vanilla-extract/blob/main/README.md#only-emitting-styles-you-use

[n8sabes]

That seems pretty cool. As 1) Qwik continues to gain traction and 2) the community continues to lean toward vanilla-extract, and 3) one of the fundamental premises of both VE and Qwik is about optimizing (minimizing) the load time while remaining pure, it seems to be a worthwhile optimization contribution as you described it. At least I would want that in my projects.

As for any technical objections or architectural impacts, it would be good to hear from @mattcompiles or other core contributors.