A second-tier port city in South Korea is emerging as the epicenter of a growing global fight over how to split the spoils of the artificial intelligence boom.Home to a mega-factory run by Samsung Electronics Co., Pyeongtaek nearly shut down this month as employees threatened a strike that risked disrupting global supply chains. The chip giant ended up offering some full-time employees in its memory division bonuses as high as $400,000 — roughly four times Samsung’s average annual salary — to de...