fix: redirect polymarket-resolution-delay + fix answer bench refs

[Flotapponnier]

Summary

Fixes 8 pre-existing smoke test failures that were causing the prod CI to auto-rollback every deploy.

• Add 308 redirect: /benchmarks/polymarket-resolution-delay → /benchmarks/pm-resolution-delay
• Update 4 answer YAMLs (best-prediction-market-for-politics, best-prediction-market-for-sports, how-long-does-polymarket-take-to-resolve, polymarket-vs-kalshi-resolution-speed) to reference pm-resolution-delay instead of the never-merged polymarket-resolution-delay bench
• Fix provider token slugs in answer templates (all-markets→polymarket-all, sports→polymarket-sports, etc.)