Homebrew tap (brew install dataGriff/tap/apic) #57

Why

On macOS and Linux, brew install is the install command people expect and the one the README's competitors show first. goreleaser generates the formula; the only new pieces are a tap repository and a token.

What

• Create dataGriff/homebrew-tap (empty repo with a README).
• Add brews: to .goreleaser.yaml: name apic, homepage, description, license MIT, install that copies the binary, installs man/ pages when present and generates completions (generate_completions_from_executable(bin/"apic", "completion")), test that runs apic version.
• release.yml gets a HOMEBREW_TAP_TOKEN secret (fine-grained PAT with contents write on the tap repo only) passed as HOMEBREW_TAP_GITHUB_TOKEN; the workflow's permissions comment is updated.
• Docs and README install tabs gain a Homebrew tab first; install.sh stays for machines without brew.
• Verify with task snapshot (goreleaser renders the formula without pushing) and then the next tag.

Where

.goreleaser.yaml, .github/workflows/release.yml, README.md, docs/getting-started.md, docs/index.md, AGENTS.md (Releasing section).

Tests

Snapshot render of the formula checked into the CI job as an artifact; a manual brew install from the tap after the first release.