fix: stabilize benchmark leaders, model benchmark sorting, and HF bucket reads

feat: refine leaderboard metrics, metadata, and visualizations

fix: tolerate unknown heatmap dataset rows

feat: refine leaderboard visualizations and CSV exports

feat: optimize bucket data caching and document refresh behavior

feat: refine leaderboard metric presentation and bucket data handling

feat: stabilize HF deploy, locale routing, and bucket caching

feat: integrate bucket-backed leaderboard data