Zohran Mamdani’s stunning performance in the Democratic mayoral primary on Tuesday amounted to a watershed moment for Muslim New Yorkers, who could see one of their own lead City Hall for the first time should he succeed in the general election in November. New York City is home to roughly one million Muslims; they made up 12 percent of the electorate in the 2021 mayoral election. Mr. Mamdani wove his faith into his campaign from its earliest days, hitting the trail while fasting for Ramadan and taking his message of affordability to mosques and Muslim community centers throughout the city....