When the Trump cabinet met at Camp David last week, the US Treasury secretary, Scott Bessent, ostentatiously put a "to do" list in front of him, where it could be seen by journalists."To Do," it said. "Buy Japanese Yen (JPY) $5 — $10 bill."Bessent used to make big currency bets for George Soros in his former life as a Wall Street banker, so knows full well the power of such signalling, even before you actually do anything.Japan and the US later announced that they had jointly intervened to prop up the yen after it had fallen to a 40-year low.Bessent…