## Why

A microphone connected during a healthy recording is currently only discovered on later device enumeration or capture recovery. Users need an explicit choice to use a newly connected headset without ending the meeting.

## What Changes

- Watch active microphone endpoints while microphone capture is running, including paused transcription.
- Offer a native Windows notification naming each newly available microphone with Yes/No actions.
- Switch only the microphone capture source when accepted, preserving system audio, transcription, and meeting artifacts.
- Ignore declined, expired, disconnected-device, and ended-meeting prompts.

## Capabilities

### New Capabilities

None.

### Modified Capabilities

- `meeting-recording`: prompt for newly available microphones and safely switch the active microphone on acceptance.

## Impact

Microphone capture orchestration, Windows notifications, dependency registration, recording documentation, and deterministic capture/notification tests. Reuses the existing Windows notification toolkit; no new UI framework or configuration migration.