RICHMOND – Jett Shane is on a mission. Shane, the son of Ryan and Kristin Shane, has a goal to raise $10,000 for the Arthritis Foundation, he said. He is about $4,000 toward that goal, Kristin Shane said. To pursue his goal, Jett Shane, his family and teammates on the Dolphin Swim Team are staging a swim-a-thon from 6-7:30 p.m. Aug. 1 at Southview Pool in Richmond. The event is open to the public, Kristin Shane said. “We’re going to have music and … people are doing donations to swim laps,” Dolphins coach Angie Pencook said July 17. “They can either do individual donations or they can do, for example, a dollar a lap or whatever.” The top three pledge-raisers will receive prizes, Pencook said. The Arthritis Foundation will apply swim-a-thon funds to multiple efforts, Kristen Shane said. “They filter it out to helping find a cure, to studies,” she said. “They have a lot of different … things that they filter it out for.” Jett Shane’s reason for raising money is personal: He has…