Polestar is deep in the development of its Polestar 5, a Porsche Taycan rival previewed by 2020’s Precept concept. The new car is set to begin sales in 2025, likely as a 2026 model. Initial development work on the sleek electric sedan was handled at Polestar’s R&D center in the U.K., and now the latest prototypes are out testing in public…