Regression: some elements don't get css scoped during SSR

[7nik]

Describe the bug

Since 5.39.3 (likely #16797), <select> doesn't receive the scoping class during SSR.
At hydration, if the class is static, it is skipped, and thus the element remains unstyled.

Reproduction

REPL - checkout the server output

Logs

System Info

Svelte@5.39.3+ (SSR)

Severity

blocking an upgrade

[LeeWxx]

@7nik I’ve also been working on this issue and have already implemented a solution, so I was just about to open a PR. If you haven’t started yet, would it be okay if I open mine and we can discuss it together?

[7nik]

Go, I'm still in the thinking and poking stage.

[LeeWxx]

@7nik Thanks for letting me know! I’ve opened a PR with a base implementation. Happy to refine it together with your feedback.