feat(attachments): 增加附件阅读解析能力

tests/test_file_summary_workflow.py

@@ -100,3 +100,27 @@ def test_stream_message_uses_normal_llm_path_when_not_triggered(monkeypatch, dja
     joined = "".join(frames)
     assert "普通回复" in joined
     assert "workflow_started" not in joined
+
+
+def test_stream_message_reads_active_attachment_when_requested(settings, tmp_path, django_user_model):
+    settings.MEDIA_ROOT = tmp_path
+    user = django_user_model.objects.create_user(username="owner", password="pass")
+    conversation = Conversation.objects.create(user=user, title="会话")
+    attachment_path = tmp_path / "uploads" / "detail.txt"
+    attachment_path.parent.mkdir(parents=True)
+    attachment_path.write_text("合同编号：RA-2026\n结论：附件阅读成功", encoding="utf-8")
+    FileAttachment.objects.create(
+        conversation=conversation,
+        user=user,
+        original_name="detail.txt",
+        storage_path="uploads/detail.txt",
+        file_size=attachment_path.stat().st_size,
+    )
+
+    frames = list(stream_message(conversation, "请阅读附件并给出详情"))
+
+    joined = "".join(frames)
+    assert "附件解析结果" in joined
+    assert "detail.txt" in joined
+    assert "RA-2026" in joined
+    assert "workflow_started" not in joined