fix(client): 审计修复——device_limit 相对时间走 relativeTime 单源+裸 Icons 换 PangolinIcons+Payment onDone 三处接通+内联双语文案收进 AppText

client/lib/screens/purchase_page.dart

@@ -38,6 +38,7 @@ class PurchaseScreen extends ConsumerStatefulWidget {
 
 class _PurchaseScreenState extends ConsumerState<PurchaseScreen> {
   AppText get t => widget.t;
+  bool get _zh => t.lang == AppLang.zh;
 
   // 支付渠道:默认 USDT·加密货币。切换即刷新套餐卡显价币种。
   PayChannel _channel = PayChannel.usdt;
@@ -59,9 +60,7 @@ class _PurchaseScreenState extends ConsumerState<PurchaseScreen> {
       // 下单失败给可见 toast,别让用户以为「点了没反应」。
       showPangolinToast(
         context,
-        t.lang == AppLang.zh
-            ? (st.errorZh ?? '下单失败，请稍后重试')
-            : (st.errorEn ?? 'Failed to create order, please retry'),
+        (_zh ? st.errorZh : st.errorEn) ?? t.orderCreateFailed,
       );
     }
   }
@@ -77,8 +76,7 @@ class _PurchaseScreenState extends ConsumerState<PurchaseScreen> {
       error: (_, __) => Center(
         child: Padding(
           padding: const EdgeInsets.all(40),
-          child: Text(t.lang == AppLang.zh ? '加载失败,请重试' : 'Failed to load, retry',
-              style: PangolinText.body.copyWith(color: c.fg3)),
+          child: Text(t.lang.loadFailedRetry, style: PangolinText.body.copyWith(color: c.fg3)),
         ),
       ),
       data: (items) {