For much of his life, Zain Javaid, 19, wanted to be a quant who uses math and data to guide his investment decisions. And for a while, he was one. But he got bored. Then, in 2022, ChatGPT was released, and he told TechCrunch, “I felt fundamentally excited in a way that I never had been before.” He became interested in personal AI, and that interest led him to start Ghost, which announced Monday that it has emerged from stealth after a year of building, along with an $11 million seed round led by...