WS: support binary finish marker; client sends 0xFF.. marker (client only sends binary chunks)

app.py

@@ -112,8 +112,14 @@ async def websocket_audio(websocket: WebSocket):
                     # Unknown text message - ignore or log
                     logger.debug(f"Unknown WS text message: {data}")
             else:
-                # Binary audio chunk
+                # Binary audio chunk (or binary control marker)
                 try:
+                    # If client sent the 4-byte control marker 0xFF 0xFF 0xFF 0xFF, treat as FINISH
+                    if isinstance(data, (bytes, bytearray)) and data == b"\xFF\xFF\xFF\xFF":
+                        result = await asyncio.get_event_loop().run_in_executor(None, server_wrapper.finish)
+                        await websocket.send_json({"type": "finish", **(result or {})})
+                        break
+
                     result = await asyncio.get_event_loop().run_in_executor(None, server_wrapper.process_chunk_from_bytes, data)
                     if result and result.get("text"):
                         await websocket.send_json({"type": "update", "text": result["text"]})
@@ -338,9 +344,9 @@ function stopRecording() {
     if (processor) processor.disconnect();
     if (source) source.disconnect();
     
-    // Send finish signal (text) so server recognizes it
+    // Send finish signal (binary marker) so server recognizes it
     if (ws && ws.readyState === WebSocket.OPEN) {
-        ws.send("FINISH");
+        ws.send(new Uint8Array([0xFF, 0xFF, 0xFF, 0xFF]));
         setTimeout(() => {
             if (ws) ws.close();
         }, 500);