## Why

Meeting Assistant can record audio on macOS, but the portable build does not register the configured global shortcuts or provide the menu-bar controls used for the normal Windows desktop workflow. macOS users must call HTTP endpoints manually.

## What Changes

- Add a native macOS menu-bar companion that starts and stops with Meeting Assistant.
- Register the same configured recording, abort, and screenshot shortcuts used on Windows.
- Expose recording/profile controls, `Open agent`, and exit from the macOS menu bar.
- Keep recording lifecycle behavior behind the existing local HTTP/service surface.

## Capabilities

### Modified Capabilities

- `meeting-recording`: configured global recording controls work on macOS.
- `meeting-session`: the desktop control menu is available from the macOS menu bar.

## Impact

- `MeetingAssistant/Native/MacOsDesktopControls`
- portable macOS build/publish output
- startup service registration
- desktop-control behavior tests and macOS runtime documentation