Read the upstream Rust (mithril-stm) end to end for STM-side types,
wrote up what we need to port, library choices, gotchas to watch,
and milestone breakdown (A: decoder, B: BLS single verify, C: Merkle,
D: lottery threshold, E: full aggregate verify, F: chain verify).
Ready for a focused crypto sprint — genesis Ed25519 + M2M plumbing
are done and shipping.
