Ensure ai_list_files always returns last_modified field

BohuTANG · BohuTANG · commit 82737203173d · 2025-11-27T23:01:27.000+08:00
diff --git a/databend_aiserver/udfs/stage.py b/databend_aiserver/udfs/stage.py
@@ -68,6 +68,7 @@ def _collect_stage_files(
             "mode": "",
             "content_type": "",
             "etag": "",
+            "last_modified": None,
         }
 
         try:
