Samsung Electronics’ biggest labour union is threatening to strike at the height of the global AI chip boom, turning a fight over bonuses into a test of how the industry’s windfall profits should be shared and sparking fears of an economic slowdown in South Korea.The union has warned it will stage an 18-day walkout from May 21 to June 7, raising concerns about production disruptions, customer defections and wider fallout across the global technology supply chain.The dispute comes as demand for...