fix(mining-app): 更新弹窗不可点击外部关闭，订单详情按买卖角色显示不同倒计时文案

- 更新提示弹窗 barrierDismissible 始终为 false，防止用户误触关闭
- 订单详情页根据买家/卖家角色显示不同的倒计时提示文案
  - 买方：你需要在xx:xx内完成付款 / 等待卖方确认收款
  - 卖方：对方将在xx:xx内完成付款 / 请在xx:xx内确认收款

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/mining-app/lib/core/updater/channels/self_hosted_updater.dart

@@ -31,7 +31,7 @@ class SelfHostedUpdater extends StatefulWidget {
   }) async {
     await showDialog(
       context: context,
-      barrierDismissible: !isForceUpdate,
+      barrierDismissible: false,
       builder: (context) => SelfHostedUpdater(
         versionInfo: versionInfo,
         isForceUpdate: isForceUpdate,

frontend/mining-app/lib/presentation/pages/c2c/c2c_order_detail_page.dart

@@ -108,7 +108,7 @@ class _C2cOrderDetailPageState extends ConsumerState<C2cOrderDetailPage> {
           const SizedBox(height: 16),
 
           // 订单状态卡片
-          _buildStatusCard(order),
+          _buildStatusCard(order, isBuyer),
 
           const SizedBox(height: 16),
 
@@ -158,7 +158,7 @@ class _C2cOrderDetailPageState extends ConsumerState<C2cOrderDetailPage> {
     );
   }
 
-  Widget _buildStatusCard(C2cOrderModel order) {
+  Widget _buildStatusCard(C2cOrderModel order, bool isBuyer) {
     Color statusColor;
     String statusText;
     String statusDesc;
@@ -176,18 +176,30 @@ class _C2cOrderDetailPageState extends ConsumerState<C2cOrderDetailPage> {
         statusColor = Colors.blue;
         statusText = '待付款';
         remainingSeconds = order.paymentRemainingSeconds;
-        statusDesc = remainingSeconds != null && remainingSeconds > 0
+        if (isBuyer) {
-            ? '对方将在 ${_formatRemainingTime(remainingSeconds)} 内完成付款'
+          statusDesc = remainingSeconds != null && remainingSeconds > 0
-            : '买方需在规定时间内付款';
+              ? '你需要在 ${_formatRemainingTime(remainingSeconds)} 内完成付款'
+              : '请在规定时间内完成付款';
+        } else {
+          statusDesc = remainingSeconds != null && remainingSeconds > 0
+              ? '对方将在 ${_formatRemainingTime(remainingSeconds)} 内完成付款'
+              : '买方需在规定时间内付款';
+        }
         statusIcon = Icons.payment;
         break;
       case C2cOrderStatus.paid:
         statusColor = Colors.purple;
         statusText = '待确认';
         remainingSeconds = order.confirmRemainingSeconds;
-        statusDesc = remainingSeconds != null && remainingSeconds > 0
+        if (isBuyer) {
-            ? '请在 ${_formatRemainingTime(remainingSeconds)} 内确认收款'
+          statusDesc = remainingSeconds != null && remainingSeconds > 0
-            : '卖方需确认收款后释放资产';
+              ? '等待卖方在 ${_formatRemainingTime(remainingSeconds)} 内确认收款'
+              : '等待卖方确认收款';
+        } else {
+          statusDesc = remainingSeconds != null && remainingSeconds > 0
+              ? '请在 ${_formatRemainingTime(remainingSeconds)} 内确认收款'
+              : '请确认收款后释放资产';
+        }
         statusIcon = Icons.check_circle_outline;
         break;
       case C2cOrderStatus.completed: