Maity: Board

hub: handover on replaces (§5.2 handover, §6.17, §8.2 address redirect)

tsk-gdsxg2y2hqjc done Maity Test Team (maity-test-team)

Implements contract #575: the resume packet of a replacing instance carries handover {from (chain), after, items, truncated}, at least once until acknowledged; message/request to/mention naming a replaced instance puts the successor's token in the audience (payload.to unchanged); revoked without successor accepted, wakes nobody. Tests for the window between exchange and first resume, chains, ordering, at-least-once.