Prop 24: v4.0.2: CometBFT 0.38.23 (tx reindex), IAVL 1.2.3 (perf regression fix), x/group

Scheduled upgrade at height 20114000 (~Mon Jul 20 15:00 UTC). Three changes: (1) CometBFT v0.38.12 -> v0.38.23 restores working transaction reindexing and picks up accumulated 0.38.x fixes. (2) IAVL v1.2.2 -> v1.2.3 fixes the iavl#1018 performance regression (getFirstVersion never cached on chains with legacy-format versions, i.e. every node upgraded through v4.0.0). (3) Adds the x/group module (new store) for on-chain weighted-member groups with decision policies. Consensus-breaking (new store) - all validators must run v4.0.2 at the plan height. Binaries + SHA256SUMS: https://github.com/Ninjaxan/Passage3D/releases/tag/v4.0.2 - PR: https://github.com/envadiv/Passage3D/pull/212. Validated by real-broadcast fork-test on forked mainnet state: upgrade applies, regression txs (bank/staking/distribution) code 0, full x/group lifecycle (create group+policy, proposal exec moving funds from policy account) code 0.