Preserve recovery transcripts and add user-approved agent requests

Append successful offline recovery with a duplicate-warning marker and retain failed replay sources. Offer newly available microphones through confirmation notifications.

Add project discovery metadata and blocking association approval, plus nonblocking workflow requests that start a separate settings-agent conversation. Include regression tests, OpenSpec changes, and verified local Release startup.

MeetingAssistant/Recording/IMicrophoneCaptureSourceFactory.cs

@@ -2,5 +2,7 @@ namespace MeetingAssistant.Recording;
 
 public interface IMicrophoneCaptureSourceFactory
 {
+    // The caller owns the returned source and disposes it when it implements IDisposable,
+    // including when capture is canceled before enumeration starts.
     IMeetingAudioSource CreateCapture(MeetingAssistantOptions options);
 }