WASHINGTON—The U.S. government on Wednesday vowed to continue battling what it sees as significant trade barriers that are harming American companies and farmers, and singled out Beijing as the “world’s leading offender” in creating overcapacities in several sectors. The U.S. Trade Representative’s office said its annual report on the issue showed “significant barriers that present major policy challenges with implications for future U.S. growth opportunities, and the fairness of the global economy.” It said it would engage with foreign governments on various issues that threaten U.S. exporters, including digital policies, agricultural trade barriers, and technical barriers. It also vowed to work to address Chinese government subsidies that have created excess capacities in the steel, aluminum, and solar sectors, and could soon affect other industries. The report made clear that U.S. Trade Representative Katherine Tai plans to continue the previous administration’s hardline approach to foreign trade practices that hamper U.S. export …