Newly discovered court documents relating to a class-action lawsuit filed against Apple and AT&T in 2007 have confirmed that the two companies originally signed a five-year iPhone exclusivity deal. Engadget quotes a briefing filed by Apple, which reads, “[t]he duration of the exclusive Apple-[AT&T] agreement was not ‘secret’ either. The [plaintiff] quotes a May 21, 2007 USA Today article – published over a month before…