Eating in the streets of Bari, Puglia, can be magical — “Mangia, mangia!” (“Eat, eat!”) said Porzia Petrone, the nearly 90-year-old Italian woman I’d met an hour earlier. We were eating lunch in her home in Bari Vecchia, the historic center of Bari in the Puglia region of southern Italy. Porzia’s daughter, Rosa, busily refreshed my plate with tuna-and-tomato bruschetta and…