Refactor quantitative benchmark reporting

[yvette-carlisle]

Summary

• Port quantitative benchmark report, product manifest, and audit manifest surfaces into split Rust modules.
• Preserve the current module split instead of restoring the old monolithic real_world_job_benchmark.rs shape.
• Clean up quantitative metric, report, manifest export/import, validation, and per-query row ownership boundaries.

Validation

• cargo make fmt-rust
• cargo test -p elf-eval --test real_world_job_benchmark quantitative::metrics -- --nocapture
• cargo test -p elf-eval --test real_world_job_benchmark quantitative::product_manifest -- --nocapture
• cargo test -p elf-eval --test real_world_job_benchmark quantitative -- --nocapture
• cargo make check-rust
• cargo make check
• git diff --check

Notes

• Branch diff at PR creation: 122 files changed, 4234 insertions(+), 467 deletions(-).
• Current largest quantitative module file: 59 lines.