feat(workflow):

1. add list operator node for filtering, sorting, limiting, and extracting list items；
2. Increase the session variable to the "file" type

api/app/controllers/app_controller.py

@@ -1079,6 +1079,14 @@ async def update_workflow_config(
         current_user: Annotated[User, Depends(get_current_user)]
 ):
     workspace_id = current_user.current_workspace_id
+    if payload.variables:
+        from app.services.workflow_service import WorkflowService
+        resolved = await WorkflowService(db)._resolve_variables_file_defaults(
+            [v.model_dump() for v in payload.variables]
+        )
+        # Patch default values back into VariableDefinition objects
+        for var_def, resolved_def in zip(payload.variables, resolved):
+            var_def.default = resolved_def.get("default", var_def.default)
     cfg = app_service.update_workflow_config(db, app_id=app_id, data=payload, workspace_id=workspace_id)
     return success(data=WorkflowConfigSchema.model_validate(cfg))