Give a card's workspace to a card that waits

When every clone is taken and an urgent card waits, the Workspaces list shows a faint menu beside each card holding a clone, with one action: give this workspace to the waiting card. After eight seconds in which it can be undone, that card's agent stops and the clone goes to the card waiting longest. Nothing is lost: what the agent had not committed is kept in a commit on its branch. The card queues again and picks up on its branch, with that work uncommitted as before, once a clone is free.