fix(html): register {@html} expression as a template reference in Svelte

[Mokto]

Summary

{@html expr} is a Svelte template tag that renders raw HTML. The expression inside it references script variables, but parse_embedded_nodes.rs had an empty arm for SvelteHtmlBlock:

AnySvelteBlock::SvelteHtmlBlock(_) => {}

This meant the identifier inside {@html html} was never registered as a template reference, causing noUnusedVariables to falsely flag the variable as unused:

<script lang="ts">
  const { html }: Props = $props();
</script>

{@html html}  <!-- html was flagged as unused ✗ -->

Fix: parse the expression inside SvelteHtmlBlock using build_svelte_text_expression_candidate and push it as an embedded snippet, the same way SvelteIfBlock, SvelteKeyBlock, and SvelteRenderBlock handle their expressions.

This PR was written primarily by Claude Code.

Test Plan

New fixture valid-svelte-at-html.svelte added to noUnusedVariables test specs. All existing tests pass.

Docs

N/A

[changeset-bot]

🦋 Changeset detected

Latest commit: 617b31a

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 13 packages

Name	Type
@biomejs/biome	Patch
@biomejs/cli-win32-x64	Patch
@biomejs/cli-win32-arm64	Patch
@biomejs/cli-darwin-x64	Patch
@biomejs/cli-darwin-arm64	Patch
@biomejs/cli-linux-x64	Patch
@biomejs/cli-linux-arm64	Patch
@biomejs/cli-linux-x64-musl	Patch
@biomejs/cli-linux-arm64-musl	Patch
@biomejs/wasm-web	Patch
@biomejs/wasm-bundler	Patch
@biomejs/wasm-nodejs	Patch
@biomejs/backend-jsonrpc	Patch

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[coderabbitai]

Walkthrough

The PR fixes a false positive in the noUnusedVariables rule for Svelte by extracting expressions from {@html ...} blocks as embedded JavaScript (TextExpression) and parsing them for analysis. It also prevents Svelte <pre> elements from being treated as generic embedded-language tags so Svelte text/interpolation nodes are produced. A new Svelte fixture and a patch changeset are included.

Possibly related PRs

• biomejs/biome#9877: Expands Svelte embed and block-kind tracking to resolve noUnusedVariables detection across various Svelte template constructs.

Suggested labels

A-Parser, L-HTML

Suggested reviewers

• dyc3

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description check	✅ Passed	The description is directly related to the changeset, explaining the root cause, the fix, and test coverage for the {@html} expression handling issue.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title accurately describes the main fix: registering {@html} expressions as template references to resolve false positives in the noUnusedVariables rule.

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✨ Finishing Touches

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[codspeed-hq]

Merging this PR will not alter performance

✅ 67 untouched benchmarks
⏩ 189 skipped benchmarks¹

---

_{Comparing Mokto:fix/svelte-at-html-reference (569e34f) with main (263c7cc)}

Footnotes

1. 189 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[ematipico]

@Mokto CI is failing, do you want to address that?