New Feature Request: Minecart Coupling

Core proposal: I am proposing an official "coupling" mechanic for Minecarts, allowing them to be linked together to form functional trains.

The Logic: With the recent update allowing boats to be attached with leads, the engine clearly supports entity towing. Since Minecarts travel on fixed rail paths, they are computationally more stable and predictable than boats. Bringing this mechanic to minecarts is a natural and highly requested evolution of the game’s infrastructure.