Added a configurable Opus bitrate for audio transcription (#981)

Co-authored-by: Thorsten Sommer <SommerEngineering@users.noreply.github.com>

app/MindWork AI Studio/Settings/DataModel/DataApp.cs

@@ -112,6 +112,18 @@ public sealed class DataApp(Expression<Func<Data, DataApp>>? configSelection = n
     /// </summary>
     public string UseTranscriptionProvider { get; set; } = ManagedConfiguration.Register(configSelection, n => n.UseTranscriptionProvider, string.Empty);
 
+    /// <summary>
+    /// The Opus bitrate used when normalizing uploaded audio/video for transcription.
+    /// </summary>
+    /// <remarks>
+    /// Every recording is re-encoded to mono Opus before it goes to the transcription provider. That
+    /// encoding used to be fixed at 32 kbps, which cost the transcription models entire quiet passages:
+    /// a greeting spoken softly at the start of a recording was simply missing from the transcript. The
+    /// same recording compared at 64 and 128 kbps came back complete, which is why 128 kbps is the
+    /// default here. Users trading accuracy for a smaller upload can still pick a lower bitrate.
+    /// </remarks>
+    public TranscriptionOpusBitrate OpusBitrate { get; set; } = ManagedConfiguration.Register(configSelection, n => n.OpusBitrate, TranscriptionOpusBitrate.KBPS_128);
+
     /// <summary>
     /// The global keyboard shortcut for toggling voice recording.
     /// Uses Tauri's shortcut format, e.g., "CmdOrControl+1" (Cmd+1 on macOS, Ctrl+1 on Windows/Linux).