Each exchange party ships a single x25519 ephemeral public (e_alice in
msg1, e_bob in msg2) and every x25519 leg is a plain DH against those
shipped keys; ML-KEM legs ship as bare ciphertexts. Encapsulation is
split into explicit ML-KEM + DH steps at the call sites, key objects
are kept as members (statics derived once from the persisted idroot,
ephemerals generated directly), and all fixed-width wire layouts are
full-message structs. Also: role-suffixed key naming throughout, dead
struct/layout cleanup.
LeoVasanko