docs: update build performance benchmarks

[github-actions]

Automated build benchmark update from workflow run #58.

[greptile-apps]

Greptile Summary

Automated benchmark update for v2.4.0 showing performance metrics, but unintentionally removed the "Lightweight Footprint" documentation section due to a regex bug in scripts/update-benchmark-report.js.

• Added v2.4.0 benchmark data (109 files, up from 99)
• Native build speed regressed 11% (1.9 → 2.1 ms/file)
• DB size per file increased 15% (3848 → 4434 bytes/file)
• Bug: The regex pattern on line 220 of the update script claims to preserve h3 subsections but actually consumes them, removing the "Lightweight Footprint" section from README.md

The benchmark regressions are at or below the 15% threshold. However, the unintended removal of documentation needs to be fixed by correcting the regex in the update script to properly preserve h3 subsections.

Confidence Score: 2/5

• Not safe to merge - removes documentation due to script bug
• The PR unintentionally deletes the "Lightweight Footprint" section from README.md because of a regex bug in the update script. While the benchmark data itself is correct, merging would remove valuable documentation.
• README.md requires attention - the "Lightweight Footprint" section needs to be restored

Important Files Changed

Filename	Overview
README.md	Updated performance metrics but unintentionally removed "Lightweight Footprint" section due to regex bug in update script
generated/BUILD-BENCHMARKS.md	Added v2.4.0 benchmark data showing 11% build speed regression and 15% DB size increase

_{Last reviewed commit: e916189}

[greptile-apps]

_{2 files reviewed, 1 comment}

_{Edit Code Review Agent Settings | Greptile}

[greptile-apps]

The "Lightweight Footprint" section (h3 subsection with dependency table) was unintentionally removed. The regex in scripts/update-benchmark-report.js:220 doesn't preserve h3 subsections as the comment claims - it matches from ## 📊 Performance to the next h2 header, consuming everything in between including the ### Lightweight Footprint subsection.

[carlos-alm]

Superseded by #121 which includes expanded benchmark format (incremental + query metrics).