fix(css): improve parsing recovery when encountering qualified rules inside CSS @page at-rule blocks

[ryan-m-walker]

Summary

closes #8428

This PR improves parsing recovery around the edge case where a user might try to use a CSS qualified rule inside an @page block. According to the spec only a declaration rule list is allowed in a @page block which treats qualified rules as invalid. This PR makes it so that qualified rules are parsed but treated as invalid. This allows us to consume the qualified rule block which would otherwise break parsing since the closing curly brace of the qualified rule would be treated as the closing brace of the @page block and cascade parsing errors further.

Note: the div:hover example in the snapshot tests still kinda breaks a bit due to it potentially being confused with a declaration but I didn't want to over-engineer the solution here with something like speculative parsing with try_parse since this mostly covers and edge case.

Test Plan

Snapshot tests

Docs

n/a

AI Usage Disclosure

I used Claude code to help explore the codebase and understand the problem a bit more and find existing solutions I could leverage, had it help me refine explanation comments, generate other test examples and double check my work but most of this was hand coded by me.

[changeset-bot]

🦋 Changeset detected

Latest commit: 65848a3

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

This PR adds parsing recovery support for CSS @page at-rules that encounter qualified rules (which are disallowed in that context). The parser now detects qualified rules within @page blocks, reports them as errors, remaps them to bogus nodes, and continues parsing subsequent declarations. The formatter was updated to handle the CssBogus variant, the grammar was expanded to permit CssBogus in page at-rule items, and recovery logic was enhanced with an additional token. Test cases verify both error recovery and valid @page constructs.

Suggested labels

A-Parser, L-CSS

Suggested reviewers

• ematipico
• dyc3

🚥 Pre-merge checks | ✅ 2

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and specifically describes the main change: improving parsing recovery for qualified rules inside CSS @page at-rule blocks, which matches the changeset perfectly.
Description check	✅ Passed	The description clearly explains the fix for issue #8428, detailing how qualified rules inside @page blocks are now parsed but marked invalid to improve recovery.

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[codspeed-hq]

Merging this PR will not alter performance

✅ 29 untouched benchmarks
⏩ 126 skipped benchmarks¹

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_{Comparing ryan-m-walker:fix/improve-parsing-recovery-in-at-rule-blocks (65848a3) with main (21dba4a)}

Footnotes

1. 126 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. ↩