More than 130 world leaders descended on the United Nations headquarters in New York this week, joining the pageantry and speechmaking of the annual general assembly.Many of the visiting presidents and prime ministers delivered their set-piece addresses to a sparsely populated hall, but contributions from two unlikely visitors in the nearby security council chamber stood out.OpenAI boss Sam Altman and Dario Amodei of Anthropic gave briefings on the safety of artificial intelligence on Wednesday, as a nervous world watched on.Speaking in the room where some of the biggest questions to face humanity have been deliberated on since the end of…