BEIJING (Reuters) —China's exports contracted last month at their fastest pace since the onset three years ago of the COVID-19 pandemic, as an ailing global economy puts mounting pressure on Chinese policymakers for fresh stimulus measures. Momentum in China's post-pandemic recovery has slowed after a brisk pickup in the first quarter, with analysts now downgrading their projections for the economy for the rest of the year as factory output slows in the face of persistently weak global demand. Outbound shipments from the world's second-largest economy slumped a worse-than-expected 12.4% year-on-year in June, data from China's Customs Bureau showed on Thursday,...