New York Rep. Alexandria Ocasio-Cortez is backing three socialist candidates challenging incumbent Democrats in next month’s primaries — including the son of a celebrity doctor and a former campaign staffer for Mayor Zohran Mamdani. The Bronx and Queens congresswoman revealed her slate of endorsements in down-ballot races Thursday, just as Mamdani shockingly boosted fellow DSA-er Darializa Avila Chevalier against longtime Manhattan Rep. Adriano Espaillat. AOC, meanwhile, announced her backing