Dalia Carmeli, who drives a trolley in downtown Miami, voted for Donald J. Trump on Election Day. A week later, she stopped in to see the enrollment counselor who will help her sign up for another year of health insurance under the Affordable Care Act. “I hope it still stays the same,” said Ms. Carmeli, 64, who has Crohn's disease and relies on her insurance to cover frequent doctor's appointments and an array of medications.