Make meeting lifecycle stateful

MeetingAssistant/Speakers/AzureSpeechSpeakerIdentityMatcher.cs

@@ -52,7 +52,15 @@ public sealed class AzureSpeechSpeakerIdentityMatcher : ISpeakerIdentityMatcher
                 return null;
             }
 
-            var segments = await diarizationClient.DiarizeAsync(tempPath, cancellationToken);
+            var segments = await DiarizeWithTimeoutAsync(tempPath, cancellationToken);
+            if (segments.Count == 0)
+            {
+                logger.LogInformation(
+                    "Speaker identity matching {DiarizedSpeaker} skipped because diarization returned no segments",
+                    request.DiarizedSpeaker);
+                return null;
+            }
+
             logger.LogInformation(
                 "Speaker identity matching {DiarizedSpeaker} received {SegmentCount} diarized segment(s)",
                 request.DiarizedSpeaker,
@@ -95,6 +103,31 @@ public sealed class AzureSpeechSpeakerIdentityMatcher : ISpeakerIdentityMatcher
         }
     }
 
+    private async Task<IReadOnlyList<TranscriptionSegment>> DiarizeWithTimeoutAsync(
+        string wavPath,
+        CancellationToken cancellationToken)
+    {
+        var matchTimeout = options.MatchTimeout;
+        if (matchTimeout <= TimeSpan.Zero)
+        {
+            return await diarizationClient.DiarizeAsync(wavPath, cancellationToken);
+        }
+
+        using var timeout = new CancellationTokenSource(matchTimeout);
+        using var linked = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken, timeout.Token);
+        try
+        {
+            return await diarizationClient.DiarizeAsync(wavPath, linked.Token);
+        }
+        catch (OperationCanceledException) when (timeout.IsCancellationRequested && !cancellationToken.IsCancellationRequested)
+        {
+            logger.LogWarning(
+                "Speaker identity diarization timed out after {Timeout}",
+                matchTimeout);
+            return [];
+        }
+    }
+
     private CompositeLayout WriteCompositeWav(string path, SpeakerIdentityMatchRequest request)
     {
         using var firstReader = OpenFirstReadableWave(request);