swap the polygon publicnode default for tenderly

[cargopete]

polygon-bor-rpc.publicnode.com fails even a 10-block getLogs a few thousand blocks behind tip, which reddened the weekly live-endpoints run (#2040). polygon.gateway.tenderly.co replaces it as the second Polygon default: archive state, 163,840-block window, topic0-only getLogs served. Twelve other keyless Polygon endpoints refused when probed today.

🤖 Generated with Claude Code

[nuthatch-jules]

Jules · merge-safety 94/100

verdict: ship

This replaces the failing Polygon fallback in src/chains.rs and updates the shipped-default probe to test the same endpoint. The two locations agree, and nothing here changes cursor behavior, storage, determinism, or the RAM budget. I checked hardest that the probe does not leave the old endpoint as an archive gate; it does not.

No findings.

_{Jules · gpt-5.6-luna · required approval · push a fix or comment /re-review to run again}