SAN FRANCISCO — In July, China unveiled a plan to become the world leader in artificial intelligence and create an industry worth $150 billion to its economy by 2030. To technologists working on A.I. in the United States, the statement, which was 28 pages long in its English translation, was a direct challenge to America’s lead in arguably the most important tech research to come along in decades. It outlined the Chinese government’s aggressive plan to treat A.I. like the country’s own version of the Apollo 11 lunar mission — an all-in effort that could stoke national pride and spark agenda-setting technology breakthroughs.