//! Unified Backend trait for CUDA, Metal, and CPU compute.
//!
//! Each backend implements the same set of transformer-layer primitives
//! (GEMM, norms, RoPE, attention, activations). `layer_forward()` and
//! `ModelRunner` are generic over `Backend`, so one forward path serves
//! all hardware targets.
pub use *;
pub use *;
pub use *;
pub use ;
pub use CpuBuf;
pub use CudaBuf;