In brief Stocks on China's mainland have lost about $2.4 trillion in market value since May, and the STAR 50 index of tech and chip companies is down 40% in under four months. AI companies make up 42% of the market value of Chinese shares and 57% of trading, per Goldman Sachs, while U.S. curbs now target Chinese robots and data center parts. Brent crude above $111 and 10-year Treasury yields near 5% are pressuring risk assets worldwide, with Bitcoin briefly under $80,000 ahead of the Fed's October 28 decision. Stocks on China's mainland have lost about $2.4 trillion in…