- Switch toolchain to stable with clippy and rustfmt components - Clean
up Clippy warnings with inline format args and hygiene fixes - Add GPU
engine placeholders (gpu-cuda, gpu-opencl) in CLI and service - Return
clear runtime error and exit for unimplemented GPU engines - Format all
TOML files with Taplo and ensure taplo fmt --check passes - Improve
mining nonce partitioning for safe range splits - Update tests to pass
cleanly on stable without warnings
rob thijssen
