Add Homebrew Cask distribution

[ngmaloney]

Summary

Make ClawChat installable via Homebrew Cask so users can brew install --cask clawchat.

Options

Option A: Separate tap repo (recommended)

• Create ngmaloney/homebrew-clawchat repo
• Add Casks/clawchat.rb pointing to the .dmg release asset
• Users install with: brew tap ngmaloney/clawchat && brew install --cask clawchat

Option B: Formula in this repo

• Add Casks/ directory here
• Tap via: brew tap ngmaloney/clawchat https://github.com/ngmaloney/clawchat
• Clutters app commit history with formula updates

Requirements

• Cask formula (not Formula — Electron apps distribute as .dmg, not built from source)
• Auto-update the cask version + SHA256 on each release (GitHub Action or manual)
• Signed .dmg release assets (already producing these via electron-builder)

References

• Homebrew Cask docs
• Tap docs