`VersionMixConsensus` quorum threshold is too low

[bboston7]

VersionMixConsensus uses a quorum threshold of 3:

2026-01-09T23:49:56.713 [default INFO] Using QUORUM_SET: {
   "t" : 3,
   "v" : [ "new-core-0", "new-core-1", "old-core-0", "old-core-1" ]
}

This means that if a single pod is slow to spin up, the network will proceed without them and (as these nodes are configured without history) the slow pod can fall behind to the point where it cannot catch up.