By JOSH BOAK and AAMER MADHANI SEOUL, South Korea (AP) — President Joe Biden tended to both business and security interests Sunday as he wrapped up a three-day trip to South Korea, first showcasing Hyundai's pledge to invest at least $10 billion in the United States and later mingling with troops at a nearby military base. Biden's visit to Osan Air Base, where thousands of U.S. and South Korean service