Until recently, young children ran in and out of their public housing homes in this Gulf Coast town, playing on sun-dappled lawns as mothers looked over their shoulders for the school bus to drop off their older kids. Suddenly, couches, dressers and refrigerators started appearing curbside for movers or garbage collectors. Within weeks, the neighborhood was a ghost town and the playground was empty. What prompted the mass exodus was a bungled message from the housing authority in Port Isabel, a South Texas community of 5,000 people, many of whom are immigrants working at hotels and restaurants on the beaches of nearby South Padre Island. The Port Isabel Housing Authority indicated a Trump administration proposal was about to take effect that would end housing assistance to families with at least one member in the country illegally. The events that followed provided a glimpse of what could happen in communities across the U.S. if the proposed rule is actually finalized.…