HUNTSVILLE, Ala. — The U.S. Army must adapt its approach to logistics to prepare for an adversary such as China, military officials say, and the service is taking steps to tackle the challenge, standing up a team tasked to develop capability that will enable troops and large amounts of equipment to deploy even in constantly contested environments. “It’s a gigantic problem, especially in the priority theater,” Gen. James Rainey, head of Army Futures Command, said at a conference in Washington,