perf(rendering): improve render performance

chore(bench): archive post-EW10 5-trial baseline

Baseline `post-EW10.json` is referenced by name in HOTSPOTS.md as the
σ-floor anchor for the cumulative paired-A/B record in the Headline
numbers section. Archiving it so the cumulative-Δ claims remain
reproducible.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>