Can it really be two years since Christopher Nolan’s film “Oppenheimer” became the old-school box-office sensation of summer 2023? Well, there you go, it must have been two years: even a journalist can do that much math. “Oppenheimer,” which is reasonably scrupulous in its accuracy by cinema standards, continues to be fertile ground for discussion and memes. People will go on talking about the war and the command decision to bomb, but the drama of Los Alamos, N.M., is a distinctive, important historical phenomenon, a little nugget of uncanny magic rearranging human history at the outset of the Jet Age.