A clothing exhibit that combines sustainability, longevity and design opens at the Buddha Barn outside Point Reyes Station on Thursday, the result of a year-long challenge to create locally crafted garments that can last generations. The challenge was set by Fibershed, a nonprofit that promotes a green regional fiber system through education, workshops, events and a membership-based network of farmers, ranchers, designers, sewers, weavers, knitters, felters, spinners, mill owners and natural dyers. The exhibit, titled…