Every card in backlog/, to-do/ and done/ gets a ⌸ chip at the end of its
footer row — the tray's own glyph — arming on the first click and
archiving on the second, through the routes and the ARCHIVE_FROM guard
that already existed. In-progress and review cards do not get one: the
board offers what it will do.
Committed by hand after the run that wrote it ended mid-turn without
committing. The work is the agent's; the suite passes on it (875 tests)
and it is unchanged from what the run left staged.
istos
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