Fix type issue in run_summary call

Pass base_path as a string to run_summary in download_scenario to ensure compatibility with expected argument types.

Author: reyery

cea/interfaces/dashboard/api/contents.py

@@ -475,7 +475,7 @@ async def download_scenario(form: DownloadScenario, project_root: CEAProjectRoot
                                     files_to_zip.append((item_path, relative_path))
                     elif output_files_level == "summary":
                         # create summary files first
-                        await run_in_threadpool(run_summary, base_path, scenario)
+                        await run_in_threadpool(run_summary, str(base_path), scenario)
 
                         export_paths = (scenario_path / "export" / "results")
                         for root, dirs, files in os.walk(export_paths):