Add Homebrew tap for macOS installation

[pikespeak]

Problem

Currently the CLI can only be installed via npm/npx or Docker. macOS developers expect brew install as a first-class installation method — especially since the prerequisites (Syft, Grype) are already installed via Homebrew.

Expected behavior

brew tap ottersight/tap
brew install ottersight

ottersight scan .

Scope

• Create a Homebrew tap repository (Ottersight/homebrew-tap)
• Add a formula for @ottersight/cli that:
  • Depends on node (or bundles a standalone binary via pkg / bun build --compile)
  • Declares anchore/grype/grype and anchore/syft/syft as dependencies
  • Installs the ottersight command to PATH
• Automate formula updates on new releases (GitHub Actions in the tap repo)

Alternatives considered

• npm only — requires Node.js knowledge, not idiomatic for macOS CLI tools
• Docker only — heavier, not suitable for quick local scans
• Standalone binary (bun/pkg) — could eliminate Node.js dependency entirely, but higher build complexity

Notes

Syft and Grype are already distributed via Homebrew taps (anchore/grype, anchore/syft), so declaring them as formula dependencies is straightforward.