已完成用户APP首期功能开发

交付用户端首期页面、配套接口、后台资源及测试文档。用户APP构建、静态分析和三个管理后台构建通过；完整测试仍有2项失败，后端模型注释检查未通过，详见交付记录。

apps/user_app/lib/domain/models/wallet_bill.dart

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+// 功能描述：钱包账单的严格金额与收支语义模型；版本：1.0.0。
+import 'client_models.dart';
+
+/// 账单是已记账事实，不把未完成订单或提现申请伪装成成功流水。
+class WalletBill {
+  const WalletBill({
+    required this.identity,
+    required this.number,
+    required this.direction,
+    required this.tradeType,
+    required this.amount,
+    required this.fee,
+    required this.balanceAfter,
+    required this.createdAt,
+    required this.channel,
+  });
+  final String identity, number, direction, tradeType, channel;
+  final int amount, fee, balanceAfter;
+  final DateTime createdAt;
+  bool get income => direction == 'income';
+  String get signedAmount => '${income ? '+' : '-'}${moneyText(amount)}';
+  String get title => switch (tradeType) {
+    'recharge' => '余额充值',
+    'refund' => '退款入账',
+    'ec_order' => '商城订单',
+    'gas_order' => '气瓶订单',
+    'withdrawal_reserve' => '提现资金冻结',
+    'withdrawal_release' => '提现资金退回',
+    'withdrawal_complete' => '提现完成',
+    _ => '其他账单',
+  };
+  factory WalletBill.fromJson(Map<String, Object?> json) {
+    int amount(String key, {bool positive = false}) {
+      final value = json[key];
+      if (value is! int || value < (positive ? 1 : 0)) {
+        throw const FormatException('账单金额格式异常');
+      }
+      return value;
+    }
+
+    final direction = json['direction'];
+    final date = DateTime.tryParse(json['created_at'] as String? ?? '');
+    if (!['income', 'expense'].contains(direction) ||
+        date == null ||
+        (json['identity'] as String? ?? '').isEmpty) {
+      throw const FormatException('账单信息不完整');
+    }
+    return WalletBill(
+      identity: json['identity'] as String,
+      number: json['record_no'] as String? ?? '',
+      direction: direction as String,
+      tradeType: json['trade_type'] as String? ?? '',
+      amount: amount('amount', positive: true),
+      fee: amount('fee'),
+      balanceAfter: amount('balance_after'),
+      createdAt: date.toLocal(),
+      channel: json['pay_channel'] as String? ?? '',
+    );
+  }
+}
+
+/// 分页游标由服务端提供，不依据客户端条数猜测是否还有数据。
+class WalletBillPage {
+  const WalletBillPage(this.items, this.nextCursor);
+  final List<WalletBill> items;
+  final String nextCursor;
+}