Nurses at two major hospital systems in New York City have reached a deal to end a nearly monthlong strike over staffing levels, workplace safety, health insurance, and other issues. The tentative agreement announced Monday by the union representing nurses involves the Montefiore and Mount Sinai hospital systems. Nurses remain on strike at NewYork Presbyterian. The walkout began Jan. 12 , prompting the hospitals to scramble to hire legions of temporary nurses to fill in during a demanding flu