feat：完成大部分数据文件上传解析功能

app/services/agent.py

@@ -9,6 +9,7 @@ from loguru import logger
 
 from app.config import settings
 from app.core.exceptions import BizException
+from app.datafiles.service import DataFileService
 from app.observability.tracing import astream_screen
 from app.processor.history import trim_history
 from app.schemas.agent import AgentResult, ResumeRequest
@@ -18,9 +19,10 @@ from app.services.conversation import ConversationStore
 
 
 class AgentService:
-    def __init__(self, graph, store: ConversationStore):
+    def __init__(self, graph, store: ConversationStore, data_files: DataFileService):
         self.graph = graph
         self.store = store
+        self.data_files = data_files
         # 同一时刻，一个任务和一个会话都只允许一个执行，避免历史顺序错乱
         self._active: set[str] = set()
         self._conversation_of: dict[str, str] = {}
@@ -40,6 +42,10 @@ class AgentService:
             turns = await self.store.load_turns(
                 conversation_id, settings.conversation_history_turns
             )
+            # 附件引用的文件不属于本会话时在流开始前返回 404
+            data_files = await self.data_files.request_files(
+                user_id, conversation_id, request.attachments
+            )
         except BaseException:
             self.release(thread_id)
             raise
@@ -57,6 +63,8 @@ class AgentService:
             ],
             settings.history_max_tokens,
         )
+        # 同样只信任服务端读取的结果；会话内的文件每一轮都可用，不附带也能查询
+        payload["data_files"] = [item.model_dump(mode="json") for item in data_files]
 
         return (
             thread_id,