TIM MCLAUGHLIN and SARAH N. LYNCH A 21-year-old member of the U.S. Air National Guard accused of leaking top secret military intelligence records online was charged with unlawfully copying and transmitting classified material. Jack Douglas Teixeira of North Dighton, Massachusetts, who was arrested by heavily armed FBI agents at his home on Thursday, made his initial appearance in a crowded federal court wearing a brown khaki jumpsuit. At the hearing, Boston's top federal national security prosecutor, Nadine Pellegrini, requested that Teixeira be detained pending trial and a detention hearing was set for Wednesday. During the brief proceeding, Teixeira said little,…