A year ago, Character.AI had the wind at its back. Founded by two artificial intelligence pioneers from Google, the startup had launched AI chatbots that offered what its far larger rivals hadn’t yet provided: something fun.Millions of people had signed up for its website and apps, intrigued by the chance to text with facsimiles of anime characters, TV personalities and historical figures in hyper-realistic roleplay. Executives discussed raising additional funding four months after Andreessen Ho...