📝 i18n: Update ratio sync message text

- Change message from "已与上游倍率完全一致，无需同步" to "未找到差异化倍率，无需同步"
- Update English translation to "No differential ratio found, no synchronization is required"
- Improve user experience clarity for upstream ratio synchronization status

web/src/pages/Setting/Ratio/UpstreamRatioSync.js

@@ -125,7 +125,7 @@ export default function UpstreamRatioSync(props) {
       setHasSynced(true);
 
       if (Object.keys(differences).length === 0) {
-        showSuccess(t('已与上游倍率完全一致，无需同步'));
+        showSuccess(t('未找到差异化倍率，无需同步'));
       }
     } catch (e) {
       showError(t('请求后端接口失败：') + e.message);