Officials in Beijing had expressed confidence that their gestures to Mr. Trump — including the lifting on Tuesday of a 14-year embargo on American beef imports — would placate Mr. Trump, whose platform as a candidate had signaled a more confrontational policy. “Why would I call China a currency manipulator when they are working with us on the North Korean problem?” he wrote in a tweet in April, defending the reversal of a campaign promise. Mr. Xi’s visit in April to Mar-a-Lago, Mr. Trump’s club in Palm Beach, Fla., underlined the importance China places on relations with the United States, and officials hoped the initial cordiality between the two leaders would establish the sort of nonconfrontational partnership that Beijing prefers.