Traders on the floor of the American Stock Exchange at the NYSE in New York on Nov. 5.Photographer: Michael Nagle/BloombergThe stock market didn’t crash this week. But after a seven-month spasm of retail-borne speculation, parts of the casino started clearing out.Cracks emerged across the risk-on landscape as bloated valuations and fresh doubts over the real-world payoff of artificial intelligence dragged US tech stocks to their worst week since April. Losses in megacaps like Palantir Technologi...