v0.1.2 alpha installer

Alpha macOS installer package for local testing. The package installs Contextual Mac Translator.app into /Applications. The app bundle is ad-hoc signed, but the installer package itself is not Developer ID signed/notarized, so macOS may require right-click Open or command-line install. SHA256: 824310dd726e26ab58a8201f2adfe598a97b9824550fdaa9631a910bf8467237