Rationale

stax releases currently ship these tarballs:

• stax-aarch64-apple-darwin.tar.gz
• stax-x86_64-apple-darwin.tar.gz
• stax-x86_64-unknown-linux-gnu.tar.gz

But there is no Linux arm64 artifact, which leaves Raspberry Pi / ARM servers unable to use the documented prebuilt-binary install path.

Evidence

• .github/workflows/release.yml only builds 3 targets today, and Linux is limited to x86_64-unknown-linux-gnu.
• README.md's "Prebuilt binaries" section documents macOS Apple Silicon, macOS Intel, and Linux x86_64 only.

Affected area

• .github/workflows/release.yml
• README.md
• homebrew-tap formula update step if checksums/assets change

Proposed improvement

Add a Linux arm64 release target, ideally aarch64-unknown-linux-gnu (or aarch64-unknown-linux-musl if static release artifacts are preferred/easier to distribute).

This would likely require:

• adding the extra target to the release matrix
• ensuring the GitHub Actions runner/toolchain can cross-build it reliably
• publishing the new tarball alongside the existing assets
• documenting the new install command in README.md
• updating checksum handling in the Homebrew/release automation if needed

Expected benefit

• Makes the prebuilt install path work on ARM Linux machines without forcing a local Rust toolchain build
• Improves first-run UX for Raspberry Pi, ARM dev boards, and ARM cloud instances
• Brings release coverage closer to the platforms already supported by the current contributor/user base