Multi-currency — Off until you need it

Most workspaces hold one currency, and for them none of this exists. There is a single switch — we record money in more than one currency — and while it is off there is one currency in play, no per-column currency picker appears anywhere, no rate table is drawn, and nothing ever asks you which currency something is in. Turning it back off genuinely turns it off: a per-column or per-record currency stored earlier is ignored rather than left quietly formatting one row differently from its neighbours. Changing a workspace's currency reinterprets existing amounts; it does not convert them. The confirmation says so in as many words — “No stored amount was changed.” Eighteen currencies are offered in the pickers.