Update Mars Credit (110110): drop dead RPC, add Blockscout explorer, add EIP155/EIP1559

[lifeofjer]

Summary

Minimal metadata update for Mars Credit (chainId 110110):

• Remove dead RPC: https://node99-production-dd5f.up.railway.app:443 returns HTTP 404 (Railway endpoint decommissioned). Keeps working RPC https://rpc.marscredit.xyz:443 (verified live, current block 0x47c3a9).
• Add explorer: Blockscout at https://blockscan.marscredit.xyz — EIP-3091 compliant (/tx/{hash} and /block/{n} both return 200).
• Add features: EIP155 and EIP1559 (London hard fork active from genesis on this go-ethereum 1.10.18 fork).

Verification

• RPC live: curl -d '{"jsonrpc":"2.0","id":1,"method":"eth_blockNumber"}' https://rpc.marscredit.xyz → {"result":"0x47c3a9"}
• Explorer live: curl -o /dev/null -w '%{http_code}' https://blockscan.marscredit.xyz/tx/0x0...0 → 200

No changes to name, infoURL, slip44, or icon. Single-file diff, prettier-formatted.

[github-actions]

You successfully submitted a PR! Due to the amount of PRs coming in: we will only look at PRs that the CI is happy with. We can also not hold your hand getting the CI green - just look how others that where merged did it and RTFM. So as long as there is any CI check that reports an error - no human will look at this. You might be able to ask for some support after supporting the project - e.g. by sending funds to lists.eth. When you fixed things after a requested change - then you also need to (re-)request a review.