Tesla Chief Executive Elon Musk said the company intends to start shipping its long-delayed Roadster sports car next year, the latest sign it is trying to inject new buzz into the brand as competition intensifies in the electric-vehicle space. In a series of posts on his social-media platform X, Musk said Wednesday that Tesla has finished its design for the vehicle as part of a collaboration between Tesla and his rocket company SpaceX, and the vehicle would be unveiled at the end of the year. “Tonight, we radically increased the design goals for the new Tesla Roadster,” Musk wrote.