A membership may name its Logins (ADR 0583 §1): the login in use and the password of each login held, kept beside the
identity, so a restart dials as the login in use. The engine follows its own key of node-logins as a watch on every link
and dials as the login it names when it holds its value, with the node's one inbox; with no key, or a key naming the first
login, it dials node.<n> with the membership's password as before. A change of the login in use drops the link so it is
opened again as the new one, and the vault is asked in the name of the login dialled (the subject names the caller).
Tests: one added, paid by merging the pinned-broker test with the malformed-pin test (two into one).
(issue 774, 774/S61)
Claude-Session: https://claude.ai/code/session_01NcbgfJ9Gum47zkFKWRaovL
jschoubben
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