cpp-desktop kits v0.20.38

C++ desktop kits for Wally local coding harnesses.

• Reports the context actually loaded after device fitting.
• Reports MLX context from the loaded model configuration.
• Includes macOS ARM64, Linux x64, Windows x64, and Windows ARM64 public kits.
• Linux targets the Ubuntu 22.04 ABI floor.

This is a desktop-kit release only; it does not publish the full cross-platform SDK package set.