CHARLOTTE, N.C. — Deebo Samuel lined up in the left slot, left his defender in the dust, cut across the end zone, and, voila, snagged Jimmy Garoppolo’s 4-yard pass for a third-and-goal touchdown. This was the offensive answer the 49ers desperately needed Sunday, for multiple reasons, en route to a 37-15 victory. Before Samuel scored, the 49ers led just 17-9, and that was cause for familiar concerns. You see, the Panthers had just pulled within one score thanks to Christian McCaffrey 19-yard, fourth-down run. That was an unpleasant reminder to the 49ers that they’d blown second-half leads in th…