Prop 13: Lumera Mainnet Upgrade v1.20.2 — Required Binary v1.20.3

Execute the on-chain upgrade plan named v1.20.2 at height 6715000. Validators must install the v1.20.3 binary in the Cosmovisor v1.20.2 upgrade directory. The v1.20.3 release contains the v1.20.2 chain upgrade logic plus a release-version stamping correction.