Follows the repo-wide rename in PR #8. Keeps the two CoinGecko-listing branches
consistent so #7 and #8 can merge in either order without reintroducing drift.
Aligns with the canonical CoinGecko doc set called out by the maintainer:
- docs/04-configuration/coingecko/COINGECKO_CHAIN138_SUBMISSION_ATTACHMENT.md
(was COINGECKO_CHAIN138_SUBMISSION_2026-04-19.md in the previous commit)
- SUPERSEDED banner link in COINGECKO_SUBMISSION_PACKAGE.md updated to the new filename.