build_osx: zip and upload .app bundles to S3

The existing "Package .zip archives" step only sweeps
\`\$install_root/bin/\` for plain executable files (via \`find -type f
-perm /111\`). That captures \`IfcConvert\` and \`IfcGeomServer\` but
misses macOS app bundles entirely:

  - BonsaiViewer.app installs at \`\$install_root/BonsaiViewer.app\`
    (BUNDLE DESTINATION ".") — not under bin/, and it's a directory,
    not a file.

So the prior bonsai macOS CI run got a green tick but the
ifcopenshell-builds S3 bucket only ended up with IfcConvert +
IfcGeomServer + the python wheel — no BonsaiViewer.

Add a second packaging pass that finds \`*.app\` directories at the
install-prefix root and zips each one as-is. macdeployqt has already
embedded the Qt frameworks inside the bundle during install/strip, so
no extra dependency staging is needed.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

.github/workflows/build_osx.yml

@@ -171,6 +171,18 @@ jobs:
               rm -rf "$package_dir"
           done
 
+          # .app bundles (e.g. BonsaiViewer.app) live at the install-prefix
+          # root because their install rule uses `BUNDLE DESTINATION "."` —
+          # that's the layout Qt's macdeployqt expects. macdeployqt has
+          # already embedded the Qt frameworks inside each bundle during
+          # install/strip, so we zip the .app as-is.
+          find "$install_root" -maxdepth 1 -type d -name "*.app" | while read app_path; do
+              app=`basename "$app_path" .app`
+              pushd "$install_root" > /dev/null
+              zip -qq -r "$HOME/output/${app}-${VERSION}-${GITHUB_SHA:0:7}-macos${{ matrix.oldarch }}64.zip" "$(basename "$app_path")"
+              popd > /dev/null
+          done
+
       - name: Configure AWS credentials
         uses: aws-actions/configure-aws-credentials@v6
         with: