refactor(batch): Isolate params state for each file processing

app.py

@@ -1592,7 +1592,7 @@ def batch_process_files(input_files, progress=gr.Progress(track_tqdm=True), *arg
         progress(i / total_files, desc=f"Processing {os.path.basename(input_path)} ({i+1}/{total_files})")
         
         # --- Pass the batch_timestamp to the pipeline ---
-        results, _ = run_single_file_pipeline(input_path, batch_timestamp, params, progress=batch_progress_updater)
+        results, _ = run_single_file_pipeline(input_path, batch_timestamp, copy.copy(params), progress=batch_progress_updater)
         
         if results:
             if results.get("final_audio_path"):