The vault holds no value for the controller's own account, the node accounts and the enrolled devices, so it cannot
hash them; the one part that has their hashes is the node-engine of the bus node, in the list the bus loaded. The have
of the bus module now carries that list's hashes sealed to the vault's key (UserListWritten.Handed), which every reader
of the have bucket sees as a count, a list digest and a key fingerprint, and only the vault opens. HandedAccountsOf
reads them from a composed list, HandAccounts seals, OpenHanded opens and refuses a box sealed to another key.
