WASHINGTON — Senate health honcho Bill Cassidy is demanding Mayor Zohran Mamdani’s team explain the hack into the NYC Health + Hospitals system in which cyber intruders lurked for over three months without detection. Cassidy (R-La.), who helms the Senate Health, Education, Labor and Pensions (HELP) Committee, raised concerns about the data breach that exposed personal information of patients in the country’s largest municipal health system. “At a time when hostile actors are increasingly using