Trevor Harris was celebrating a birthday and, suitably enough, there were cards, cards, cards. Football and hockey cards were in abundance! The cardboard celebration was a production of Upper Deck, which invited several players to a Wednesday afternoon signing session during Coors Light Riders Training Camp. Harris and an assortment of Saskatchewan Roughriders teammates were autographing labels that will be affixed to Upper Deck sports-memorabilia items — most conventionally, CFL cards. “It’s pretty cool,” receiver Jake Wieneke said while scribbling on some of his 390 labels. “I always give a bunch of cards to my family.” A few tables away,…