Chinese technology stocks surged Thursday and the U.S. and China agreed to hold a virtual summit before year-end between its two leaders. But the challenges for Chinese companies—and U.S.-China relations— persist. Chinese technology stocks got a short reprieve Thursday, buoyed by a broader sense of relief in the market as U.S. policymakers, for now, averted a showdown over the U.S. debt ceiling. E-commerce giant Alibaba (ticker: BABA) rose 7.3% in Hong Kong, with the U.S.-listed stock up 9.4%—on track for its best day in more than four years, when the shares jumped 13.3% in one day during June 2017. Didi...