SDXL runtime source derived from mlx_diffuser at commit
a26b42aee4e31999dbb4429226b66d896d49e1d8:
https://github.com/amirhossein-razlighi/mlx_diffuser

Original work by Amirhossein Razlighi and contributors, released under CC0 1.0.
Rapid-MLX modifications narrow the runtime to SDXL, add an in-loop progress and
cancellation hook, and adapt image results to Rapid-MLX's image engine contract.
