ADR 0401-0408 graduate research 055: no release branch, two more ordering
rules, the composed check as each member's gate, a backup before the send,
installed toolchains, events and work queues on the bus, the merge window
as keys, and one chain kept on the bus alone. Design 47 is rewritten from
them (one design per thing); the glossary takes hotfix, feature, toolchain,
milestone and epic and retires release branch; design 18 loses the
toolchain image; playbooks 07 and 08 drop the release-branch wait.