New York City’s real estate market typically begins the year on the sleepy side. But, this time around, there’s apparently no waiting for the spring buying season, according to a report Thursday by StreetEasy. Citywide, the number of homes going into contract jumped 10.7% in January compared to a year ago, while the median asking price fell 2.1%, according to the listing and data site. Contracts, though, slipped 5.2% from December.