Scott Tolman and Mallory Brubaker are ready for swimming’s next challenge: a year-round program. But before they go, the Manteca Dolphins’ brightest stars hope to make one last splash at the Mid-Valley Swim League Championships.Tolman and Brubaker are runaway favorites to earn high-point honors Saturday at Lathrop High in what will likely be their final swim with Manteca’s longstanding rec club.Dolphins assistant coach Niki DeGeorge believes both record-setting swimmers are ready for their transition to a year-round program with Ripon Aquatics. What gives her that kind of confidence?