Normalize Comment Terminology

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

Util/Audio/Mixer/VoiceMixer.cs

@@ -35,7 +35,7 @@ internal sealed class VoiceMixer : IDisposable
         Change
     }
 
-    /// <summary>Command queued by the main thread and taken by the render thread at the start of <see cref="Mix"/>.</summary>
+    /// <summary>Command queued by the main Unity thread and taken by the render thread at the start of <see cref="Mix"/>.</summary>
     private readonly struct Command
     {
         public readonly CommandKind Kind;
@@ -55,7 +55,7 @@ internal sealed class VoiceMixer : IDisposable
     private readonly AudioClipStore _store;
     private readonly CancellationToken _cancellationToken;
 
-    // Double-buffered command lists: the main thread appends to _commands under _commandLock; the render thread swaps the
+    // Double-buffered command lists: the main Unity thread appends to _commands under _commandLock; the render thread swaps the
     // two lists under the lock and processes _takenCommands outside it, then clears it for the next swap.
     private readonly object _commandLock = new();
     private List<Command> _commands = new();
@@ -126,7 +126,7 @@ internal sealed class VoiceMixer : IDisposable
 
     /// <summary>
     /// Queues a change of <paramref name="voice"/> that takes effect at sample <see cref="ToSample"/>(<paramref name="time"/>).
-    /// Called by the Voice Set methods on the main thread.
+    /// Called by the Voice Set methods on the main Unity thread.
     /// </summary>
     internal void Enqueue(Voice voice, Voice.ChangeKind kind, double time, double value)
     {