fix typo

app.py

@@ -1056,12 +1056,12 @@ class WhisperTranscriber:
             # Clean up preprocessed wav
             if pre_meta:
                 for pre_meta in pre_metas:
-                    for chunk in pre_meta["segments"]:
-                        if chunk.get("out_wav_path") and os.path.exists(chunk["out_wav_path"]):
-                            try:
-                                os.unlink(chunk["out_wav_path"])
-                            except Exception:
-                                pass
+                    chunk = pre_meta["chunk"]
+                    if chunk.get("out_wav_path") and os.path.exists(chunk["out_wav_path"]):
+                        try:
+                            os.unlink(chunk["out_wav_path"])
+                        except Exception:
+                            pass
     
     @spaces.GPU           # each call gets a GPU slice
     def process_audio_diarization(self, task_json, num_speakers=0):