chore: standardize non-UTF-8 benchmark names

[hyfdev]

Summary

• rename dirty_before_non_utf8 to non_utf8_dirty_before
• require every non-UTF-8 timed benchmark leaf name to start with non_utf8
• keep the renamed benchmark identifier the same length so this naming-only baseline does not perturb compiled layout

Why this is separate

This behavior-neutral baseline PR lands the benchmark identity before #47 is stacked on it. CodSpeed can then compare the implementation against the same non_utf8_dirty_before identity on both sides instead of reporting one removed row and one new row.

Validation

• cargo fmt --all --check
• cargo bench --locked --no-run

[codspeed-hq]

Merging this PR will improve performance by 12.87%

⚠️ 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
✅ 225 untouched benchmarks
🆕 2 new benchmarks
⏩ 38 skipped benchmarks¹

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
⚡	Simulation	string	255.8 ns	226.7 ns	+12.87%
🆕	Simulation	non_utf8_dirty_before	N/A	2.5 µs	N/A
🆕	Memory	non_utf8_dirty_before	N/A	68 B	N/A

Tip

Curious why this is faster? Comment @codspeedbot explain why this is faster on this PR, or directly use the CodSpeed MCP with your agent.

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_{Comparing agent/non-utf8-benchmark-prefix (1e1c882) with main (5f4a1bd)}

Footnotes

1. 38 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. ↩

[Copilot]

Pull request overview

Standardizes naming for non-UTF-8 benchmark leaf names so CodSpeed/Criterion summaries remain recognizable and comparable across baseline/stacked performance PRs, aligning with the project’s benchmark identity stability goals.

Changes:

• Updated benchmark naming guidance to require non_utf8 as a leaf-name prefix for non-UTF-8 inputs.
• Renamed the timed benchmark leaf dirty_before_non_utf8 to non_utf8_dirty_before (same string length) and aligned the local variable name accordingly.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
benchmarks/README.md	Documents the “non-UTF-8 leaf names must start with non_utf8” convention for stable, recognizable benchmark rows.
benches/hot_path_baselines.rs	Renames the affected non-UTF-8 timed benchmark leaf to the standardized non_utf8_* prefix form.

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