RENTON, Wash. — When Tyler Lockett is reminded that he is now No. 1 in terms of continuous service time on the Seahawks, he says jokingly, “You’re making me feel old.” In football years, 29 can seem ancient. And seven going on eight years with one organization, in a sport that is constantly churning personnel, can be an eternity. So it’s undeniable that Lockett has entered the wise, old-head stage of his Seahawks career, particularly with the departures of elder statesmen Bobby Wagner and Russell Wilson in the offseason. With such seniority comes responsibility, which Lockett has earned throug…