Written by Chris Buckley, Alexandra Stevenson and Keith Bradsher The southwestern city of Chongqing was the latest frontline of Xi Jinping’s “zero-Covid” war, until it came to epitomise China’s potentially devastating about-face that has cracked the Communist Party’s edifice of absolute control. The city last month was enduring one of the biggest outbreaks cropping up across China, when the national leader, Xi, ordered officials to continue mass testing, lockdowns and quarantines. Chen Min’er, the Chongqing party secretary, devoutly complied, closing off neighbourhoods and ordering the instant construction of a quarantine hospital designed to hold up to 21,000 beds. “Be resolute…