MIAMI, FLORIDA — About 600,000 Venezuelans and more than 230,000 Salvadorans already living in the United States can legally remain another 18 months, the Department of Homeland Security said Friday, barely a week before President-elect Donald Trump takes office with promises of hard-line immigration policies. Biden’s administration has strongly supported Temporary Protected Status, which he has expanded to cover about 1 million people. TPS faces an uncertain future under Trump, who tried to sharply curtail its use during his first term as president. Federal regulations would allow the extensions to be terminated early, although that’s never been done before. Homeland