Add support for `pq-devnet-3`

[pq-devnet-3 high-level plan](https://github.com/leanEthereum/pm/blob/main/breakout-rooms/leanConsensus/pq-interop/pq-devnet-3.md)

Devnet 3 has a tentative target of 2026-02-25. We should start working on the spec changes and new features introduced by it.