“In the coming months, I and my team will build a City Hall capable of delivering on the promises of this campaign,” Mamdani, a democratic socialist, said at his first news conference as mayor-elect. “We will form an administration that is equal parts capable and compassionate, driven by integrity and willing to work just as hard as the millions of New Yorkers who call this city home.” That transition team will include two former deputy mayors, Maria Torres-Springer and Melanie Hartzog; former Federal Trade Commission Chair Lina Khan; and Grace Bonilla, the head of United Way of New York City,...