## Why

The portable macOS application can capture meeting audio and expose menu-bar controls, but it still registers unavailable/no-op implementations for calendar metadata, recording prompts, and active-window screenshots. The local macOS environment also disables screenshot OCR, speaker identification, the managed FunASR backend, FunASR diarization, and Whisper-local diarization even though their managed implementations are portable.

## What Changes

- Read Teams meeting metadata and prompt candidates from calendars available through macOS EventKit, including Outlook-synced calendars.
- Show a native macOS record/skip prompt for due calendar meetings.
- Capture the foreground macOS application window through a bundled native helper so screenshot OCR can use the existing portable OCR pipeline.
- Register the real macOS integrations instead of no-op/unavailable providers.
- Enable the portable OCR, speaker identification, FunASR, and diarization configuration in the macOS runtime environment.
- Expose a diagnostic capability surface that proves the effective platform providers and enabled feature switches.
- Preserve all Windows-specific COM, notification, screenshot, tray, hotkey, and audio registrations.

## Capabilities

### Modified Capabilities

- `meeting-session`: calendar enrichment, recording prompts, workflow editor access, and capability diagnostics work on macOS.
- `meeting-summary`: active-window screenshots and screenshot OCR work on macOS.
- `meeting-transcription`: portable speaker identification, FunASR, and local diarization can be enabled on macOS.

## Impact

- portable service registration in `MeetingAssistant/Program.cs`
- a bundled native macOS desktop-integration helper
- calendar, meeting-metadata, screenshot, and diagnostic providers
- macOS runtime configuration and operational documentation
- macOS behavior tests plus Windows-target build verification