hotfix v2.18.1

This release distributes the approved nibid binaries for the v2.18.1 mainnet security upgrade.

hotfix/v2.18.1 is an artifact-distribution tag. It intentionally does not identify the source tree used to build these binaries. More information will be added to the repository post-upgrade.

Verify the archive before installation:

sha256sum -c nibid_2.18.1_checksums.txt

Pre-stage the matching Linux binary before the scheduled upgrade height. Operators with Cosmovisor binary downloading enabled may use the Linux URLs in the governance upgrade plan.