fix(import): close each style block's open @media before joining blocks

[tommy230]

Summary

If one <style> block on an imported page is missing a closing }, every <style> block after it ends up inside that block's media query. The later rules then apply only at that breakpoint.

<style>.nav a{color:#fff}@media (max-width:600px){.nav{display:none}</style>
<style>.nav a{color:#1e1e1e}</style>

A browser parses each <style> element as its own stylesheet, so the open @media ends with the first block. The importer joins the blocks into one string before parsing, which loses that boundary.

The fix closes whatever each block leaves open (braces, a comment, a string) before joining. Braces inside comments and strings are ignored. Balanced blocks are left unchanged.

Verification

• bun run build
• bun run lint
• bun test: 7056 pass, 0 fail
• Docker/deployment check, if relevant: not relevant

New tests in src/__tests__/htmlImport/mapping.test.ts fail on main and pass with this change.

Checklist

• Tests cover behavior changes.
• Docs were updated when behavior, config, deployment, or public surfaces changed.
• No compatibility shim was added for old pre-release behavior.
• No secrets, local databases, uploads, or generated artifacts are included.

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