Normalize Comment Terminology

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

Util/FrameReader.cs

@@ -26,7 +26,7 @@ namespace ADOFAIRenderer.Util
     /// (RenderManager.SendVideoFrame, then <see cref="RecycleState"/>) or the frame was dropped.
     /// </para>
     /// <para>
-    /// Threads: requests and readback completions run on the main thread; <see cref="RecycleState"/> is also called by
+    /// Threads: requests and readback completions run on the main Unity thread; <see cref="RecycleState"/> is also called by
     /// the render thread. The pool and the disposed flag are guarded by _poolLock. One instance per render, created in
     /// RenderManager.SetupPlay with the pixel format of the opened encoder.
     /// </para>
@@ -290,7 +290,7 @@ namespace ADOFAIRenderer.Util
 
         /// <summary>
         /// Returns a state to the pool after its frame was sent or dropped, or disposes it when the reader is disposed.
-        /// Called by the render thread (after sending) and by the main thread (abort, errors, queue cleanup).
+        /// Called by the render thread (after sending) and by the main Unity thread (abort, errors, queue cleanup).
         /// </summary>
         internal void RecycleState(ReadbackRequestState state)
         {