feat: change segment_size to decimal in Product model

api_v1/test_mingdaoyun_utils.py

@@ -1,4 +1,5 @@
 import asyncio
+from decimal import Decimal
 from unittest.mock import patch
 
 from django.test import SimpleTestCase
@@ -99,7 +100,7 @@ class MingDaoYunParsersTestCase(SimpleTestCase):
         self.assertEqual(product.created_at, "2025-12-01 00:00:00")
         self.assertEqual(product.name, "产品A")
         self.assertEqual(product.pieces, 12)
-        self.assertEqual(product.segment_size, 3)
+        self.assertEqual(product.segment_size, Decimal("3"))
         # width 与 segment_size 当前共用同一个 controlId；保持同步代码现状
         self.assertEqual(product.width, "3")
         self.assertEqual(product.unit, "米")