hex-devices

Introduced Hexagon device support for discovery and on-demand session creation, including lazy allocation and runtime NPU core discovery. Non-existing devices are now rejected early during initialization.

This release introduces significant enhancements to the Hexagon backend, including multi-NPU device support, a fully asynchronous backend, and improved performance for various operations like ALLREDUCE and matrix multiplications. It also includes numerous bug fixes and optimizations across different Hexagon modules.