feat(c2c): 前端添加 Bot 自动购买信息展示

- C2cOrderModel 添加 botPurchased/sellerKavaAddress/paymentTxHash 字段
- 订单详情页新增 Bot 支付信息卡片，显示 dUSDT 交易哈希
- 支持复制 Kava 地址和交易哈希

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

frontend/mining-app/lib/data/models/c2c_order_model.dart

@@ -46,6 +46,10 @@ class C2cOrderModel {
   final int confirmTimeoutMinutes;        // 确认收款超时时间（分钟）
   final DateTime? paymentDeadline;        // 付款截止时间
   final DateTime? confirmDeadline;        // 确认收款截止时间
+  // Bot 自动购买相关
+  final bool botPurchased;                // 是否被 Bot 购买
+  final String? sellerKavaAddress;        // 卖家 Kava 地址
+  final String? paymentTxHash;            // dUSDT 支付交易哈希
   // 其他
   final C2cOrderStatus status;
   final String? remark;
@@ -79,6 +83,10 @@ class C2cOrderModel {
     this.confirmTimeoutMinutes = 60,
     this.paymentDeadline,
     this.confirmDeadline,
+    // Bot 自动购买相关
+    this.botPurchased = false,
+    this.sellerKavaAddress,
+    this.paymentTxHash,
     // 其他
     required this.status,
     this.remark,
@@ -118,6 +126,10 @@ class C2cOrderModel {
       confirmDeadline: json['confirmDeadline'] != null
           ? DateTime.parse(json['confirmDeadline'])
           : null,
+      // Bot 自动购买相关
+      botPurchased: json['botPurchased'] ?? false,
+      sellerKavaAddress: json['sellerKavaAddress'],
+      paymentTxHash: json['paymentTxHash'],
       // 其他
       status: _parseOrderStatus(json['status']),
       remark: json['remark'],
@@ -190,6 +202,7 @@ class C2cOrderModel {
   bool get isPaid => status == C2cOrderStatus.paid;
   bool get isCompleted => status == C2cOrderStatus.completed;
   bool get isCancelled => status == C2cOrderStatus.cancelled;
+  bool get isBotPurchased => botPurchased && paymentTxHash != null;
 
   String get typeText => isBuy ? '买入' : '卖出';
 

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

@@ -113,6 +113,13 @@ class _C2cOrderDetailPageState extends ConsumerState<C2cOrderDetailPage> {
           // 订单信息
           _buildOrderInfoCard(order, isMaker),
 
+          // Bot 支付信息卡片（Bot 购买的卖单显示）
+          if (order.isBotPurchased)
+            ...[
+              const SizedBox(height: 16),
+              _buildBotPaymentInfoCard(order),
+            ],
+
           // 收款信息卡片（已匹配或已付款状态时显示）
           if (order.hasPaymentInfo &&
               (order.isMatched || order.isPaid))
@@ -177,7 +184,7 @@ class _C2cOrderDetailPageState extends ConsumerState<C2cOrderDetailPage> {
       case C2cOrderStatus.completed:
         statusColor = _green;
         statusText = '已完成';
-        statusDesc = '交易已完成';
+        statusDesc = order.isBotPurchased ? 'Bot 已自动购买并支付 dUSDT' : '交易已完成';
         statusIcon = Icons.verified;
         break;
       case C2cOrderStatus.cancelled:
@@ -460,11 +467,141 @@ class _C2cOrderDetailPageState extends ConsumerState<C2cOrderDetailPage> {
     );
   }
 
+  /// Bot 支付信息卡片
+  Widget _buildBotPaymentInfoCard(C2cOrderModel order) {
+    return Container(
+      margin: const EdgeInsets.symmetric(horizontal: 16),
+      padding: const EdgeInsets.all(20),
+      decoration: BoxDecoration(
+        color: _green.withOpacity(0.05),
+        borderRadius: BorderRadius.circular(12),
+        border: Border.all(color: _green.withOpacity(0.3)),
+      ),
+      child: Column(
+        crossAxisAlignment: CrossAxisAlignment.start,
+        children: [
+          Row(
+            children: const [
+              Icon(Icons.smart_toy, size: 20, color: _green),
+              SizedBox(width: 8),
+              Text(
+                'Bot 自动购买',
+                style: TextStyle(
+                  fontSize: 16,
+                  fontWeight: FontWeight.bold,
+                  color: _darkText,
+                ),
+              ),
+            ],
+          ),
+          const SizedBox(height: 16),
+
+          // 支付说明
+          Container(
+            padding: const EdgeInsets.all(12),
+            decoration: BoxDecoration(
+              color: _green.withOpacity(0.1),
+              borderRadius: BorderRadius.circular(8),
+            ),
+            child: Row(
+              children: const [
+                Icon(Icons.check_circle, size: 16, color: _green),
+                SizedBox(width: 8),
+                Expanded(
+                  child: Text(
+                    'Bot 已自动购买您的卖单，dUSDT 已转入您的 Kava 地址',
+                    style: TextStyle(fontSize: 13, color: _darkText),
+                  ),
+                ),
+              ],
+            ),
+          ),
+
+          const SizedBox(height: 12),
+
+          // 收款地址
+          if (order.sellerKavaAddress != null)
+            _buildPaymentInfoRow(
+              label: '收款地址',
+              value: _truncateAddress(order.sellerKavaAddress!),
+              canCopy: true,
+              copyValue: order.sellerKavaAddress,
+            ),
+
+          // 支付金额
+          _buildPaymentInfoRow(
+            label: '支付金额',
+            value: '${formatAmount(order.totalAmount)} dUSDT',
+          ),
+
+          // 交易哈希
+          if (order.paymentTxHash != null)
+            _buildPaymentInfoRow(
+              label: '交易哈希',
+              value: _truncateAddress(order.paymentTxHash!),
+              canCopy: true,
+              copyValue: order.paymentTxHash,
+            ),
+
+          // 查看交易链接
+          if (order.paymentTxHash != null) ...[
+            const SizedBox(height: 12),
+            InkWell(
+              onTap: () => _openExplorer(order.paymentTxHash!),
+              child: Container(
+                padding: const EdgeInsets.symmetric(vertical: 8),
+                child: Row(
+                  mainAxisAlignment: MainAxisAlignment.center,
+                  children: const [
+                    Icon(Icons.open_in_new, size: 16, color: _orange),
+                    SizedBox(width: 4),
+                    Text(
+                      '在区块链浏览器中查看',
+                      style: TextStyle(
+                        fontSize: 13,
+                        color: _orange,
+                        fontWeight: FontWeight.w500,
+                      ),
+                    ),
+                  ],
+                ),
+              ),
+            ),
+          ],
+        ],
+      ),
+    );
+  }
+
+  /// 截断地址显示
+  String _truncateAddress(String address) {
+    if (address.length <= 16) return address;
+    return '${address.substring(0, 8)}...${address.substring(address.length - 8)}';
+  }
+
+  /// 打开区块链浏览器
+  Future<void> _openExplorer(String txHash) async {
+    // Kava 区块链浏览器
+    final url = 'https://kavascan.com/tx/$txHash';
+    // 这里可以使用 url_launcher 包打开链接
+    // 暂时只复制交易哈希
+    Clipboard.setData(ClipboardData(text: url));
+    if (mounted) {
+      ScaffoldMessenger.of(context).showSnackBar(
+        const SnackBar(
+          content: Text('区块链浏览器链接已复制'),
+          duration: Duration(seconds: 2),
+        ),
+      );
+    }
+  }
+
   Widget _buildPaymentInfoRow({
     required String label,
     required String value,
     IconData? icon,
     bool canCopy = false,
+    String? copyValue,
   }) {
     return Padding(
       padding: const EdgeInsets.symmetric(vertical: 8),
@@ -493,7 +630,7 @@ class _C2cOrderDetailPageState extends ConsumerState<C2cOrderDetailPage> {
                 const SizedBox(width: 8),
                 GestureDetector(
                   onTap: () {
-                    Clipboard.setData(ClipboardData(text: value));
+                    Clipboard.setData(ClipboardData(text: copyValue ?? value));
                     ScaffoldMessenger.of(context).showSnackBar(
                       const SnackBar(
                         content: Text('已复制'),