//! Gradient utilities (legacy shim).
//!
//! The Candle-based gradient clipping and NaN detection functions have been
//! removed. GPU gradient operations are now handled by:
//!
//! - `cuda_autograd::GpuAdamW` — built-in gradient norm clipping per step.
//! - Loss functions in `cuda_autograd::LossKernels` — produce gradient tensors
//!   directly, no separate `GradStore`.
//!
//! This module is kept as an empty placeholder so that `pub mod gradient_utils`
//! in `lib.rs` compiles. Downstream crates should migrate to the cuda_autograd
//! equivalents.