v0.2.0 — Homebrew cask support

Casks

metalbrew can now install macOS apps and vendor binaries from Homebrew's cask index — no Ruby, no sudo by default, self-contained under the metalbrew prefix.

metalbrew cask install rectangle      # .dmg app  -> ~/Applications
metalbrew cask install iterm2         # .zip app  -> ~/Applications
metalbrew cask install ngrok          # binary    -> <prefix>/bin
metalbrew cask uninstall <token>      # reverses placement + runs zap/uninstall directives
metalbrew cask info / list / upgrade

Supported artifacts

• .zip and raw .app bundles → ~/Applications
• binary → copied into the Caskroom and symlinked into <prefix>/bin
• .tar.gz
• .dmg → mounted via hdiutil, app copied out, detached
• .pkg → only with --allow-sudo / METALBREW_ALLOW_SUDO (runs Apple's installer)

Details

• Downloads stage under <prefix>/Caskroom/<token>/<version>/; apps land in ~/Applications.
• Uninstall honors cask uninstall/zap directives (delete, trash, quit, pkgutil, launchctl).
• com.apple.quarantine is intentionally kept — Gatekeeper still vets apps on first launch.
• sha256 :no_check casks download with a printed warning; checksummed casks are verified as before.
• New end-to-end CI matrix installs real casks across every no-sudo path and verifies uninstall.

Built on a clean hexagonal seam (new Runner subprocess port); the formula install path is unchanged.