The global economy has proved stubbornly resilient this summer, even as the backdrop has grown noisier. A fresh flare-up in the Middle East, reports of official intervention to arrest a slide in the yen, and a bout of nerves over the vast sums now being committed to artificial intelligence have all unsettled sentiment, while central banks — the Federal Reserve among them — have turned markedly more hesitant about cutting rates than they appeared only a few months ago. Yet the incoming data have held up better than feared, with a broad gauge of global activity climbing back above its normal tre...