Add uses_sys_files_for_node flag to node calls

Introduces the uses_sys_files_for_node parameter to knowledge retrieval and question classifier node calls, enabling more explicit control over system file usage. Also cleans up redundant imports in the LLM node implementation.

api/core/workflow/nodes/knowledge_retrieval/knowledge_retrieval_node.py

@@ -458,6 +458,7 @@ class KnowledgeRetrievalNode(LLMNode):
             vision_detail=node_data.vision.configs.detail,
             variable_pool=self.graph_runtime_state.variable_pool,
             jinja2_variables=[],
+            uses_sys_files_for_node=False,
         )
 
         result_text = ""

api/core/workflow/nodes/llm/node.py

@@ -5,6 +5,9 @@ import logging
 from collections.abc import Generator, Mapping, Sequence
 from typing import TYPE_CHECKING, Any, Optional, cast
 
+from sqlalchemy import select
+from sqlalchemy.orm import Session
+
 from core.app.entities.app_invoke_entities import ModelConfigWithCredentialsEntity
 from core.file import FileType, file_manager
 from core.helper.code_executor import CodeExecutor, CodeLanguage
@@ -68,10 +71,6 @@ from core.workflow.nodes.event import (
     RunStreamChunkEvent,
 )
 from core.workflow.utils.variable_template_parser import VariableTemplateParser
-
-# --- New imports for file-usage persistence ---
-from sqlalchemy.orm import Session
-from sqlalchemy import select
 from extensions.ext_database import db
 from models.model import NodeFileUsage
 
@@ -218,7 +217,6 @@ class LLMNode(BaseNode[LLMNodeData]):
                                     )
                             session.commit()
                     except Exception:
-                        # Non-critical – failure to persist should not break node execution
                         pass
 
             if files:

api/core/workflow/nodes/question_classifier/question_classifier_node.py

@@ -101,6 +101,7 @@ class QuestionClassifierNode(LLMNode):
             vision_detail=node_data.vision.configs.detail,
             variable_pool=variable_pool,
             jinja2_variables=[],
+            uses_sys_files_for_node=node_data.vision.enabled and bool(node_data.vision.configs.variable_selector),
         )
 
         result_text = ""