On a Friday night in Melbourne, before 100,000 witnesses who had never seen professional American football played on their soil, the San Francisco 49ers defeated the Los Angeles Rams 27-7 — not merely winning a game, but inaugurating a new chapter in the long story of sport's capacity to cross oceans and find new hearts. Quarterback Brock Purdy's three touchdown passes were the instrument; the Melbourne Cricket Ground was the stage; and the NFL's restless ambition to become a truly global institution was the quiet force behind it all. Some milestones announce themselves loudly, and some simply