Chinese artificial intelligence start-up DeepSeek closed its first-ever external fundraising in an unusual and high-stakes deal that could not only reshape the country’s AI landscape but also offer a rare glimpse into how one of China’s most valuable AI start-ups will navigate its next phase of growth, sources and analysts said.Hangzhou-based DeepSeek now has a post-investment value of about 400 billion yuan (US$59.2 billion) after raising around 50 billion yuan in a Series A round, one source...