feat: health check trustless gateways before first use

[SgtPooki]

try multiple gateways, and if available, set as trustless gateways for @helia/verified-fetch

[lidel]

Idea:

• prewarm reliability weights for trustless gateways by requesting some well-known small CID which should return payload instantly, and allow us to identify offline and slow gateways
  • This allows us to include http://127.0.0.1:8080 (Kubo/IPFS Desktop) and http://127.0.0.1:48080 (Brave)
  • Caveat: be careful if using identity CID, as these are often returned from local virtual store and not trigger network IO.