fix(client/orders): 过期单动作改「重新购买」(orderRebuy),不再用歧义的「继续支付」

过期单 pay 会话已失效,点击本质是重新下单;expired 与 canceled 同用 orderRebuy。

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013nMthbVEmQquxBRKb9Fj8u

client/lib/screens/orders_page.dart

@@ -328,8 +328,9 @@ class _OrderDetailView extends ConsumerWidget {
       final list = <Widget>[];
       switch (o.status) {
         case 'created':
-        case 'expired':
           list.add(PangolinButton(label: t.orderContinuePay, expand: true, onPressed: () => _goPurchase(context, ref)));
+        // 过期单 pay 会话已失效,点击是重新下单而非续付 → 用「重新购买」避免歧义。
+        case 'expired':
         case 'canceled':
           list.add(PangolinButton(label: t.orderRebuy, expand: true, onPressed: () => _goPurchase(context, ref)));
         case 'paid':