BENTONVILLE, AR — In a somber press conference held just steps from the seasonal bin of half-melted phone chargers, Walmart executives issued a stark warning Monday: rising tariffs on Chinese imports may severely disrupt the company’s ability to stock products precisely engineered to break one minute after their 1-year warranty expires. “For decades, our customers have trusted us to deliver air fryers, vacuum cleaners, and children’s tablets that work beautifully until exactly one calendar...