fix(macos): preserve audio when transcription fails

MeetingAssistant.Tests/RecordingCoordinatorTests.cs

@@ -1378,6 +1378,45 @@ public sealed class RecordingCoordinatorTests
         Assert.False(audioArchive.Deleted);
     }
 
+    [Fact]
+    public async Task StopQueuesAzureBacklogAndRetainsAudioWhenTranscriptionFails()
+    {
+        var audioSource = new ControlledAudioSource();
+        var provider = new FailingAfterFirstAudioProvider();
+        var audioArchive = new InMemoryRecordedAudioStore();
+        var backlog = new InMemoryOfflineTranscriptionBacklog();
+        var coordinator = new MeetingRecordingCoordinator(
+            audioSource,
+            new TestSpeechRecognitionPipelineFactory(provider),
+            new InMemoryTranscriptStore(),
+            new InMemoryMeetingNoteStore(),
+            new CapturingMeetingNoteOpener(),
+            new InMemoryMeetingArtifactStore(),
+            audioArchive,
+            new CapturingMeetingSummaryPipeline(),
+            Options.Create(new MeetingAssistantOptions
+            {
+                Recording = new RecordingOptions
+                {
+                    TranscriptionProvider = "azure-speech"
+                }
+            }),
+            NullLogger<MeetingRecordingCoordinator>.Instance,
+            offlineTranscriptionBacklog: backlog);
+
+        await coordinator.StartAsync(CancellationToken.None);
+        await audioSource.WriteAsync(new AudioChunk([1, 0], 16000, 1), CancellationToken.None);
+        await provider.WaitUntilFailureObservedAsync();
+
+        var stopped = await coordinator.StopAsync(CancellationToken.None);
+
+        Assert.False(stopped.IsRecording);
+        var item = Assert.Single(backlog.Items);
+        Assert.Equal("memory-recording.wav", item.AudioPath);
+        Assert.True(audioArchive.Completed);
+        Assert.False(audioArchive.Deleted);
+    }
+
     [Fact]
     public async Task OfflineBacklogReplaysQueuedRecordingAndCompletesMeetingArtifacts()
     {
@@ -4988,6 +5027,31 @@ public sealed class RecordingCoordinatorTests
         }
     }
 
+    private sealed class FailingAfterFirstAudioProvider : IStreamingTranscriptionProvider
+    {
+        private readonly TaskCompletionSource failureObserved =
+            new(TaskCreationOptions.RunContinuationsAsynchronously);
+
+        public Task WaitUntilFailureObservedAsync()
+        {
+            return failureObserved.Task.WaitAsync(TimeSpan.FromSeconds(5));
+        }
+
+        public async IAsyncEnumerable<TranscriptionSegment> TranscribeAsync(
+            IAsyncEnumerable<AudioChunk> audio,
+            SpeechRecognitionPipelineOptions options,
+            [System.Runtime.CompilerServices.EnumeratorCancellation] CancellationToken cancellationToken)
+        {
+            await foreach (var _ in audio.WithCancellation(cancellationToken))
+            {
+                failureObserved.TrySetResult();
+                throw new InvalidOperationException("Configured transcription backend is unavailable.");
+            }
+
+            yield break;
+        }
+    }
+
     private static byte[] Samples(params short[] samples)
     {
         var bytes = new byte[samples.Length * sizeof(short)];
@@ -4995,6 +5059,3 @@ public sealed class RecordingCoordinatorTests
         return bytes;
     }
 }
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