fix: force FramePlayer to WASM-only render mode; document CORS policy intent

DeepDrftPublic.Client/Pages/FramePlayer.razor

@@ -5,6 +5,7 @@
 
 @page "/FramePlayer"
 @layout EmbedLayout
+@rendermode InteractiveWebAssembly
 
 <AudioPlayerBar Fixed />
 

DeepDrftPublic/Program.cs

@@ -77,6 +77,9 @@ else
     }
 }
 
+// CORS policy registered for hygiene and potential direct cross-origin API consumers.
+// The FramePlayer embed use case does not require this: WASM inside a cross-site iframe
+// fetches to the same deepdrft.com origin, so all API calls are same-origin.
 app.UseCors("FramePlayerEmbedPolicy");
 
 // For requests to /FramePlayer, remove any X-Frame-Options header and set a permissive