NEW YORK — A New York City Fire Department firefighter was arrested after allegedly purchasing an assault weapon, large-capacity ammunition and “ghost gun” parts from a Philadelphia gun show and smuggling them back to the city, officials said Sunday. Firefighter Aaron Martin was hit with numerous felony weapons possession charges after he was arrested in Queens following a multiagency joint investigation. Members of the Queens County district attorney’s office Detective Bureau followed Martin to the “Oaks Extravaganza” gun show at the Greater Philadelphia Exposition Center Feb. 13, according t…