Add zero-length file check in _list_checkpoints function of app.py to skip empty files during checkpoint listing. This enhancement improves the robustness of file handling by preventing errors related to empty files.

app.py

@@ -184,6 +184,10 @@ def _list_checkpoints(out_dir: str, limit: int = 20) -> List[str]:
                 if fn.lower().endswith('.safetensors'):
                     full = os.path.join(root, fn)
                     try:
+                        # Skip files that are zero-length or currently being written
+                        size = os.path.getsize(full)
+                        if size <= 0:
+                            continue
                         items.append((os.path.getmtime(full), full))
                     except Exception:
                         pass