Raw FFI bindings to the vendored VkFFT C++ library.

This crate is internal plumbing for the gpufft crate. It exposes the minimal subset of VkFFT needed to initialize an FFT application from a Rust-built VkFFTConfiguration, append dispatches to a caller-allocated Vulkan command buffer via VkFFTAppend, and release resources on drop.

Safety

Every item in this crate is unsafe by construction. Lifetimes of the Vulkan handles and of the storage backing the VkFFTConfiguration pointer fields are the caller's responsibility. Downstream crates should depend on gpufft instead, which wraps these calls in a typed API.