fn talk_then(held: &Held, now: &Now) -> (String, Vec<Column>)Expand description
Which row and which cells “Let them through then” sets for a held
conversation (let_talk_then): the person’s own row by their card, else
by their number, else the conversation’s; under do-not-disturb that layer,
in a slot of time for you that one, during work Work and Admin together,
else the time now.