fix(rng): reject resource references without href

[gaborbernat]

Users can compile <externalRef/> and <include/> without the href required by the RELAX NG full syntax. Reject these incomplete patterns in roots, reachable patterns and unused definitions.

The Jing label runner now compares the two inline missing-attribute cases as compilation rejections. This completes their ordinary compilation checks in #1016.

This builds on the private-tree annotation removal and unused-reference traversal merged in #1198.

The Atheris environment includes the structural reducer’s tinycss2 dependency so the public consumer inventory can import.

[codspeed]

Merging this PR will regress 1 benchmark

⚠️ Different runtime environments detected

Some benchmarks with significant performance changes were compared across different runtime environments,
which may affect the accuracy of the results.

Open the report in CodSpeed to investigate

⚡ 1 improved benchmark
❌ 1 regressed benchmark
✅ 579 untouched benchmarks
⏩ 32 skipped benchmarks¹

Warning

Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Benchmark	BASE	HEAD	Efficiency
❌	test_feature[select-relative-sibling]	43.2 µs	45.5 µs	-5%
⚡	test_feature[shadow-slot-comments]	110.3 µs	83.6 µs	+31.9%

Tip

Investigate this regression by commenting @codspeedbot fix this regression on this PR, or directly use the CodSpeed MCP with your agent.

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_{Comparing gaborbernat:fix/rng-inline-resource-labels-1016 (bc7fd28) with main (9ff1626)}

Footnotes

1. 32 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. ↩