5d9054154c
Remove the separate bdist_dmg build step and instead package the generated .app in-place: create a .app.zip and build a UDZO .dmg using a temporary dmg_stage (copy .app, add Applications symlink, run hdiutil). Also remove the previous fallback that searched for prebuilt DMGs and change missing .app handling to error+exit. Artifacts are written to artifacts/YTSage-v${version}-${ARCH_SUFFIX}.{app.zip,dmg}.