Some of the world’s biggest carmakers are squaring off for a titanic battle over small cars in Europe, as native stalwarts like Volkswagen and Renault fight to maintain their hold on the market against an influx of cheap electric vehicles (EVs) from BYD and its Chinese peers.Last month, BYD, which surpassed Tesla last year as the world’s largest EV maker, launched its Dolphin Surf compact hatchback in Europe. The company’s most affordable model, known in China as the Seagull, is priced from...