refactor(generator): simplify file extraction logic

- Standardize file extraction using `args.get("files") or []` pattern
- Improve readability and consistency across app generators

api/core/app/apps/agent_chat/app_generator.py

@@ -49,7 +49,12 @@ def generate(
     ) -> dict: ...
 
     def generate(
-        self, app_model: App, user: Union[Account, EndUser], args: Any, invoke_from: InvokeFrom, stream: bool = True
+        self,
+        app_model: App,
+        user: Union[Account, EndUser],
+        args: Any,
+        invoke_from: InvokeFrom,
+        stream: bool = True,
     ) -> Union[dict, Generator[dict, None, None]]:
         """
         Generate App response.
@@ -100,7 +105,7 @@ def generate(
         role = CreatedByRole.ACCOUNT if isinstance(user, Account) else CreatedByRole.END_USER
 
         # parse files
-        files = args["files"] if args.get("files") else []
+        files = args.get("files") or []
         file_extra_config = FileUploadConfigManager.convert(override_model_config_dict or app_model_config.to_dict())
         if file_extra_config:
             file_objs = file_factory.build_from_mappings(

api/core/app/apps/workflow/app_generator.py

@@ -68,7 +68,7 @@ def generate(
         call_depth: int = 0,
         workflow_thread_pool_id: Optional[str] = None,
     ):
-        files: Sequence[Mapping[str, Any]] = args.get("files", [])
+        files: Sequence[Mapping[str, Any]] = args.get("files") or []
 
         role = CreatedByRole.ACCOUNT if isinstance(user, Account) else CreatedByRole.END_USER