rk 0.1.8

• Homebrew is now Formula-only throughout inspection, staging, manifests, and
  tap updates. RK no longer reads, converts, or removes legacy Cask state.
• Binary and Homebrew initialization now defaults to the current host's native
  platform, so a Linux host does not silently propose a macOS artifact it
  cannot produce. Cross-builds remain explicit configuration choices.
• Docker and Podman capability probes are bounded and run only for releases
  that ship binaries. Missing or unresponsive runtimes remain optional and
  degrade cross-build smoke evidence instead of blocking publication.