Chevrolet's Bolt is back for 2027, giving GM another lower-cost electric vehicle to sell. Yet even as sales start to improve, dealers are still holding unusually large numbers of them, raising questions about their sales success. So the main question is whether GM got demand wrong or if this is part of a plan to purposefully stock dealer lots before the Bolt goes away again. What's happening? Part of what makes the inventory buildup so notable i…