feat(macos): add native desktop controls and hotkey integration

- Introduced MacOsDesktopControlManifest to manage desktop control configurations.
- Implemented MacOsDesktopControlService to handle the lifecycle of the macOS helper process.
- Created MacOsWorkflowRulesEditorWindowService for managing workflow rules through a native window.
- Developed a Swift helper for macOS that integrates with AppKit and Carbon for menu-bar controls and global hotkeys.
- Added support for recording lifecycle actions via HTTP endpoints, maintaining consistency with existing Windows functionality.
- Enhanced user experience by allowing macOS users to start/stop recordings and access settings through a menu-bar interface.
- Documented design decisions, implementation evidence, and verification tasks for the new macOS features.

openspec/changes/add-macos-desktop-controls/proposal.md

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+## 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