By Eduardo Baptista and David Stanway BEIJING/SHANGHAI (Reuters) -Beijing residents fretted on Friday over tightening COVID curbs in its biggest district and dozens of new cases reported daily as China’s leaders reiterated their resolve to battle the virus and threatened action against critics of their strict measures. Incurring a heavy economic cost and facing rare public criticism on its tightly-policed internet, China is increasingly out of step with the rest of the world where COVID restrictions are being abandoned and vaccines relied on to protect people. Internationally, industry organisations have complained that China’s ‘zero-COVID’ policies have global economic reverberations. At...