Add macOS console build and packaging

[jochenwezel]

The console architecture is intended to support macOS, but release packaging currently focuses on Windows and experimental Linux x64.

Scope:

• add macOS runtime publishing if the backend can compile cleanly
• decide package format for macOS console builds
• document installation and runtime requirements
• validate device discovery and available camera controls

Related commits:

• c430b01 Add console backend abstraction and Linux preview asset
• 829fca8 Allow console app to roll forward to newer dotnet runtimes
• 6457ad0 Add cross-platform metadata config and camera test scripts