NEW YORK — The Taylor Swift serial stalker accused of repeatedly showing up outside the music icon’s Tribeca townhouse was found mentally unfit to stand trial and has been committed to psychiatric care, Manhattan prosecutors said. The decision came during a brief Manhattan Criminal Court hearing Friday for Seattle resident David Crowe, who was sitting in a jail cell for repeatedly showing up at the “Shake It Off” crooner’s Franklin Street apartment in January. An examination by a mental health professional found that “David Crowe is unfit to stand trial,” a spokesman for Manhattan D.A. Alvin B…