Package otari-cli for Homebrew

[njbrake]

Note: this issue was drafted by Claude via back-and-forth with @njbrake. The reasoning and decisions are his; the prose is Claude's.

Provide a Homebrew formula so macOS users (and Linux users via Homebrew) can brew install otari-cli.

Context: otari-cli 0.1.0 is now on PyPI (see #4).

Tasks:

• Create a Homebrew formula that installs from the PyPI sdist, following Homebrew's Python virtualenv formula pattern with resource stanzas for runtime dependencies (otari, typer, rich, httpx).
• Decide on a tap: a mozilla-ai/homebrew-tap repo, or submission to homebrew-core once the project meets notability requirements.
• Wire formula version bumps to releases (manual at first, automated on tag later).
• Verify brew install provides the otari command end to end.

Note: toto suggested doing this alongside the snap packaging.