[hey-research-lab]

Every explorer link the UI builds for Robinhood Chain (account, tx and token) points at explorer.mainnet.chain.robinhood.com. That host serves no explorer: the TLS handshake is refused, so each link fails to open.

$ curl -sv https://explorer.mainnet.chain.robinhood.com/ 2>&1 | grep -E "Connected|alert"
* Connected to explorer.mainnet.chain.robinhood.com (172.66.147.70) port 443
* LibreSSL/3.3.6: error:1404B410:SSL routines:ST_CONNECT:sslv3 alert handshake failure

The chain's explorer is Blockscout at https://robinhoodchain.blockscout.com. It's the explorer in the chain registry entry (ethereum-lists eip155-4663.json) and in viem's robinhood chain, and it serves the same /address/, /tx/ and /token/ paths that explorerUrl builds.

Change. EXPLORER_HOST.robinhood.host now points at robinhoodchain.blockscout.com. I also added src/lib/chains.test.ts (included in npm test), which checks the three Robinhood link kinds.

Tested. The new test fails before the change (actual: 'https://explorer.mainnet.chain.robinhood.com/address/…') and passes after it. I ran the rest of npm test without installing dependencies: it gives 65 pass / 7 fail both before and after this change. The 7 failures are the test/*.test.mjs server suites, which need the installed packages.