SURPRISE, Ariz. — Manager Mike Matheny believes the Kansas City Royals are poised for a breakthrough, and even if it happens next season, he’ll be in the dugout when the franchise returns to the playoffs for the first time since 2015. The Royals announced Thursday they had exercised their club option on Matheny’s contract for the 2023 season. Terms of the deal were not disclosed. “There’s no place I’d rather be than here, in the middle of something really special,” Matheny said prior to the team’s morning workout at their spring training facility in Arizona. “A special group of players. A spec…