Together, Mrs. Yang and Mrs. Kim have fostered over 140 children in Korea. Last month, they visited Holt families in Oregon — an experience they, and the adoptees and adoptive families they met, will never forget. Mrs. Yang sat in a room at Holt’s international headquarters in Oregon — sobbing. She clutched the glossy photobook to her chest then set it down to cover her face with her hands. The photobook was sent to her by a Holt family, and…