fix(cache): bump keys for cellRanks + quorum guard on partial renders

[Flotapponnier]

Summary

• bench-unfiltered-v5 → v6 and all-benchmarks-v7 → v8: cached Benchmark objects from pre-cellRanks deploys lack the field, which made region-scoped badge URLs 404 and the products index serve stale draft-cycle wins (the repo's documented bump-on-shape-change rule, missed in the cellRanks PR)
• Scoped badge 404s now carry s-maxage=60 so a transient miss can't get pinned by the CDN for the route's 300s revalidate window
• Quorum guard in tryLoadLive: a Prom brownout that times out most providers used to yield a "live" render with 1 bar on the leaderboard, cached for 60s and overwriting the KV snapshot with the degraded set (seen on prod rpc-capabilities showing only 1RPC). Sub-50% unfiltered renders now count as a failed cycle: unstable_cache keeps the last good render, the snapshot is not overwritten. Filtered chain/region views are exempt since they legitimately have fewer providers.

Test plan

• tsc + bun test pass
• After staging deploy: /api/badge/rpc-capabilities/drpc?region=sgp returns 200, /products index shows dRPC per-chain wins, bench pages never render sub-quorum leaderboards