SANTA CLARA, Calif. — Christian McCaffrey sauntered through the 49ers’ locker room Friday with a gold, 49ers’ helmet in his right hand, along with his new, No. 23 jersey. Rather than go straight to his locker next to George Kittle, McCaffrey spotted defenders lurking nearby, as he’s prone to do. So McCaffrey headed directly for linebacker Dre Greenlaw and safety Talanoa Hufanga as they sat side-by-side at their lockers. This was a re-introduction. Two Sundays ago, McCaffrey juked those defenders en route to his 50th and final touchdown for the Carolina Panthers, who lost that game 37-15, and, …