feat: 持久化资料包导出记录与列表摘要

tests/test_chat.py

@@ -9,7 +9,7 @@ from apps.audit.models import AgentAuditLog
 from apps.audit.models import NotificationRecord
 from apps.chat.models import Conversation
 from apps.chat.services import create_conversation_for_batch
-from apps.documents.models import SubmissionBatch, UploadedDocument
+from apps.documents.models import ExportedDocument, SubmissionBatch, UploadedDocument
 
 
 def _create_conversation_with_batch():
@@ -547,3 +547,4 @@ def test_chat_export_word_route_persists_real_download_link(client, db, tmp_path
     assert "下载导出文件" in content
     assert export_report["download_url"] in content
     assert AgentAuditLog.objects.filter(conversation_id=conversation.conversation_id).count() == 1
+    assert ExportedDocument.objects.filter(batch=batch, conversation_id=conversation.conversation_id).count() == 1