Rust Skeleton VHAL implementation.

WARNING: This is not a reference VHAL implementation and does not contain any actual implementation.

This folder contains a skeleton VHAL implementation in Rust to demonstrate how vendor may implement a Rust VHAL. To run this VHAL, include android.hardware.automotive.vehicle-V3-rust-service in your image.

This implementation returns StatusCode::UNKNOWN_ERROR for all operations and does not pass VTS/CTS. Vendor must replace the logic in default_vehicle_hal.rs with the actual implementation.