v1.0.0

feat(build): cross-compile Linux binaries from macOS

Allow developers to build Linux executables directly from macOS systems.

• Added 64-bit (amd64) and 32-bit (i386) targets
• Configured Musl toolchain via Homebrew
• Documented process in BUILD.md
• Added verification step with 'file' command

BREAKING CHANGE: Requires brew install musl-cross