Fitness-industry darling Peloton launched its Internet-enabled smart stationary bike—the company’s very first commercial product—just 4 years ago. In that short time, it quickly amassed a legion of dedicated—even cultish—fans who regularly tune in to participate in live and on-demand cycling lessons with professional trainers and compete with other cyclists around the world. This year at CES, the Manhattan-based brand officially expanded its unique, tech-driven …