Every day, Nidia Montenegro spends hours checking her cellphone, hoping to receive a long-awaited appointment with U.S. border officials to seek asylum in the United States. The 52-year-old Venezuelan migrant in Mexico says she fears her appointment will not come before President-elect Donald Trump takes office on Jan. 20, when he has vowed to scrap a slew of programs that have allowed migrants to enter the U.S. legally - including the government app that Montenegro is using to try...