Apple on Monday rolled out a long-delayed overhaul of Siri, betting the upgraded ?assistant can help close the gap with Big Tech rivals ?and new-age startups in the crucial AI race.The revamp, unveiled at its annual Worldwide Developers Conference in Cupertino, California, introduces "Siri ?AI," a more conversational assistant with a standalone app and the ability to analyze what is on a user's screen and pull in information from the web. The update comes two years after Apple first promised major upgrades that were repeatedly delayed.Apple said users would be able to revisit past Siri conversations, while the assistant can...