Improve Lyapunov benchmark performance reporting

[jamestjsp]

Summary

• optimized BB04AD examples 4.1/4.2 scaling loops by replacing repeated pow() calls with recurrence-based scaling
• added a benchmark report section for rows where Fortran is faster, sorted by largest advantage
• completed and committed the ergo performance epic state

Validation

• uv pip install .
• .venv/bin/pytest tests/python/test_bb04ad.py -v
• .venv/bin/pytest tests/python/test_benchmark_report.py -v
• .venv/bin/pytest tests/python/test_bb03ad.py tests/python/test_bb04ad.py -v
• .venv/bin/meson setup build-bench-c -Dbuild_benchmarks=true --wipe
• .venv/bin/meson compile -C build-bench-c
• .venv/bin/python scripts/benchmark_c_vs_fortran.py --c-build-dir build-bench-c --output benchmark_c_vs_fortran_report.md -r bb03ad bb04ad

Final generated report showed no BB03AD/BB04AD row more than 1.5x slower than Fortran; remaining Fortran-faster rows were BB04AD ex4.4 at 1.11x, 1.07x, and 1.06x.

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 651278524f

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

[chatgpt-codex-connector]

Fix inverted ratio reported as F77/C11

The new Fortran Faster Rows table labels the column as F77/C11 Ratio, but the value is computed as c_mean_us / f_mean_us (C11/F77). This inverts the meaning of every reported ratio and can mislead performance decisions (for example, C11=40 and F77=20 is shown as 2.00x even though F77/C11 is 0.50x). Please either compute f_mean_us / c_mean_us or relabel the column to match the current formula.

Useful? React with 👍 / 👎.

[jamestjsp]

Fixed in 1594fe1 by relabeling the column to F77 Advantage, matching the existing C11-time / F77-time formula and sort order. The focused report-rendering test was updated and passes.