fix: SSR scoped classes for <select value> elements

[LeeWxx]

Fixes #16813

Server-rendered <select> elements stopped getting their scoped CSS because the special select branch skipped the hashing/directive merge. I pass the hash and directive data through to $$renderer.select, then let the existing attributes(...) helper merge them so the flow matches other elements. If there’s a better way to do this, I’m happy to adjust. Added a renderer unit test and an SSR sample to cover the regression.

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pnpm add https://pkg.pr.new/svelte@16821

[7nik]

Another bug from that PR is async attributes are awaited twice. I guess build_element_attributes on ~40 line should be called only if the element won't have special handling.

[LeeWxx]

@7nik. Thanks for the review! I’ve applied all three points:

– Added prepare_element_spread to share object/css_hash/classes/styles/flags logic
– Simplified renderer.select to fixed args
– Skipped early build_element_attributes in special <select> branch

I’d value your thoughts. I’m happy to adjust if needed.

[LeeWxx]

@7nik Thanks for pointing that out! I had overlooked <option>. I’ve added a guard and updated it so that both <select>and <option> now go through the shared prep and attributes.

[7nik]

LGTM, thank you!

[svelte-docs-bot]

Preview: https://svelte-dev-git-preview-svelte-16821-svelte.vercel.app/