On a narrow street lined with row houses and an auto body shop in the Kensington neighborhood of North Philadelphia, Marsella Elie climbs a home’s front steps and knocks hard on the door. A middle-aged man appears with a wary look on his face. “Hello, sir, how are you doing today?” asked Elie, wearing a royal-blue jacket embroidered with the city government’s Liberty Bell logo. “My name is Marsella. I’m working with the city. You heard about the overdoses that are going around in the neighborhood, right?” The man gives a cautious nod. Elie gestures to the pamphlets she’s holding about drug ove…