WASHINGTON — A federal appeals court on Friday required the Trump administration to continue allowing lawmakers to inspect immigration detention facilities without advance notice, ruling unanimously that the impromptu visits posed minimal problems for the government. The decision by a three-judge panel of the Court of Appeals for the District of Columbia Circuit preserved, for now, the ability of Democrats in Congress to make unannounced visits to detention centers and check on the conditions inside. Related It came as the Trump administration is working to dramatically expand the Department of Homeland Security’s detention capacity with converted warehouses and as detention facilities have repeatedly drawn allegations of human rights violations.…