CAN THO, Vietnam — Dao Bao Tran and her brother Do Hoang Trung, 11-year-old twins growing up on a rickety houseboat in the Mekong Delta, have dreams. Nguyen Thi Thuy, a vendor selling steamed buns on a floating market, ignites a fire on her boat while getting ready for her day’s work in Can Tho, Vietnam, Wednesday, Jan. 17, 2024. …