Illustration: Tyler Comrie So many people had signed up for China’s premier artificial-intelligence expo in mid-July — over 200,000 by some estimates — that the ticketing system had crashed. A mob of frustrated AI enthusiasts had formed outside as a result. “How could they do this to us?” one woman cried. “Report the venue! Dial 12345!” a man hollered, evoking the Chinese equivalent of 311. A decade ago, people around the world traveled to Silicon Valley to glimpse the future. These days, they come to China. Inside the expo spanning more than 14 football fields, visitors watched robot workers assemble…