release: v4.2.1 - Add Linux ARM64 (aarch64-unknown-linux-gnu) build target to tool-rust template - Projects using tool-rust component now automatically build for three platforms: * macOS ARM64 (darwin-arm64) * Linux x86_64 (linux-amd64) * Linux ARM64 (linux-arm64) ← NEW - build:linux-arm64 job: Compiles with cargo zigbuild for aarch64-unknown-linux-gnu - sign:linux-arm64 job: Cosign-signs binary and SBOM - publish and release jobs updated with linux-arm64 artifacts - Release notes templates include linux-arm64 install instructions No breaking changes. Existing projects continue to work as-is. New projects or projects tagging after this release will automatically get linux-arm64 binaries.