No output generated on MacOS to Companion app

Describe the bug Attempting to generate a PDF on MacOS does not produce any output to the Companion app. The app hangs in the call to ShowInCompanion() but no output is displayed. (related to issue #1293)

To Reproduce Set up a simple Razor app using the default "Getting started" code. Run it.

Expected behavior Something should appear in the Companion app.

Screenshots If applicable, add screenshots to help explain your problem.

Environment MacOS Sequoia, Dotnet 9.0.8

Additional context Hopefully this gets more (some?) attention than my last report (#1293)