Set up CodSpeed performance measurement

[codspeed-hq]

Summary

This PR fixes the existing CodSpeed CI workflow so it runs correctly on a personal GitHub account, and adds a CodSpeed badge to the README.

Changes

CI Workflow (.github/workflows/codspeed.yml)

• Changed runner from codspeed-macro to ubuntu-latest. Macro runners are only available for organization repositories, not personal accounts.
• Changed Python architecture from arm64-freethreaded to x64-freethreaded to match the x64 architecture of ubuntu-latest runners.

README

• Added the CodSpeed performance badge.

Note on walltime variance

Because this is a personal account, codspeed-macro runners are not available. The workflow uses ubuntu-latest instead, which means walltime measurements will have significantly higher variance than with dedicated bare-metal runners. For more details, see the walltime documentation on personal accounts.

Benchmarks validated locally

All 6 benchmarks across the 3 rounds were validated and pass:

• test_bench_compute_histogram[baseline] / [solution]
• test_bench_find_corruptions[baseline] / [solution]
• test_bench_find_matches[baseline] / [solution]

Next steps

• If this repository moves to an organization, switch the runner back to codspeed-macro for lower-variance walltime measurements.
• Optionally set a DATASET_SEED secret to make generated datasets reproducible across CI runs.

[codspeed-hq]

Congrats! CodSpeed is installed 🎉

🆕 6 new benchmarks were detected.

You will start to see performance impacts in the reports once the benchmarks are run from your default branch.

⚠️ Unknown Walltime execution environment detected

Using the Walltime instrument on standard Hosted Runners will lead to inconsistent data.

For the most accurate results, we recommend using CodSpeed Macro Runners: bare-metal machines fine-tuned for performance measurement consistency.

Detected benchmarks

• test_bench_compute_histogram[solution]: 3.5 s
• test_bench_find_matches[baseline]: 2.1 s
• test_bench_find_corruptions[baseline]: 3.7 s
• test_bench_compute_histogram[baseline]: 3.5 s
• test_bench_find_matches[solution]: 2.1 s
• test_bench_find_corruptions[solution]: 3.6 s

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