BEIJING/HONG KONG — After Donald Trump first stormed the White House eight years ago, rattled Chinese leaders responded to his tariffs and fiery rhetoric with force, resulting in a trade war that plunged ties between the globe’s largest economies to multiyear lows. This time around, Beijing has been preparing for Trump’s return by deepening ties with allies, boosting self-reliance in tech, and setting aside money to prop up the economy that is now more vulnerable to fresh tariffs already threatened by Trump. While some retaliation to those moves might be unavoidable, China will focus on exploiting rifts between the U.S.