A guy named I-HYUN picked up 46,000 Instagram followers before his boy band put out a single song. He isn't real. Neither are the other four members, and as of today, fans can text every one of them. The group is called muuo:23, it's out of Seoul, and every member was generated by AI. The single dropped today alongside the group's own app, and the main feature is a private AI chat with each member. You message TAEWON, he writes back, and the company says the relationship grows from…