SAN FRANCISCO — Tech companies are racing to upgrade chatbots like ChatGPT not only to offer answers, but also to take control of a computer to take action on a person’s behalf.Experts in artificial intelligence and cybersecurity warn the technology will require people to expose much more of their digital lives to corporations, potentially bringing new privacy and security problems.In recent weeks, executives from leading AI companies including Google, Microsoft, Anthropic and OpenAI have all pr...