refactor: 将前端从 uni-app x 重构为 Flutter

变更内容:
- 删除 uni-app x 项目 (app/ 目录)
- 新增 Flutter 项目 (flutter_monisuo/ 目录)
- 新增部署脚本 (deploy/ 目录)

Flutter 项目功能:
- 用户登录/注册
- 首页资产概览
- 行情币种列表
- 交易买卖操作
- 资产账户管理
- 充值/提现/划转
- 深色主题
- JWT Token 认证

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

flutter_monisuo/lib/data/models/coin.dart

@@ -0,0 +1,106 @@
+/// 币种模型
+class Coin {
+  final int id;
+  final String code;
+  final String name;
+  final String? icon;
+  final double price;
+  final double? priceUsd;
+  final double? priceCny;
+  final int priceType; // 1=实时价格, 2=管理员设置
+  final double change24h;
+  final double? high24h;
+  final double? low24h;
+  final double? volume24h;
+  final int status;
+  final int sort;
+
+  Coin({
+    required this.id,
+    required this.code,
+    required this.name,
+    this.icon,
+    required this.price,
+    this.priceUsd,
+    this.priceCny,
+    required this.priceType,
+    required this.change24h,
+    this.high24h,
+    this.low24h,
+    this.volume24h,
+    required this.status,
+    this.sort = 0,
+  });
+
+  factory Coin.fromJson(Map<String, dynamic> json) {
+    return Coin(
+      id: json['id'] as int? ?? 0,
+      code: json['code'] as String? ?? '',
+      name: json['name'] as String? ?? '',
+      icon: json['icon'] as String?,
+      price: (json['price'] as num?)?.toDouble() ?? 0,
+      priceUsd: (json['priceUsd'] as num?)?.toDouble(),
+      priceCny: (json['priceCny'] as num?)?.toDouble(),
+      priceType: json['priceType'] as int? ?? 1,
+      change24h: (json['change24h'] as num?)?.toDouble() ?? 0,
+      high24h: (json['high24h'] as num?)?.toDouble(),
+      low24h: (json['low24h'] as num?)?.toDouble(),
+      volume24h: (json['volume24h'] as num?)?.toDouble(),
+      status: json['status'] as int? ?? 1,
+      sort: json['sort'] as int? ?? 0,
+    );
+  }
+
+  Map<String, dynamic> toJson() {
+    return {
+      'id': id,
+      'code': code,
+      'name': name,
+      'icon': icon,
+      'price': price,
+      'priceUsd': priceUsd,
+      'priceCny': priceCny,
+      'priceType': priceType,
+      'change24h': change24h,
+      'high24h': high24h,
+      'low24h': low24h,
+      'volume24h': volume24h,
+      'status': status,
+      'sort': sort,
+    };
+  }
+
+  /// 显示图标（Unicode 符号）
+  String get displayIcon {
+    const icons = {
+      'BTC': '\u20BF',
+      'ETH': '\u039E',
+      'SOL': '\u25CD',
+      'USDT': '\u20AE',
+      'DOGE': '\uD83D\uDC15',
+      'XRP': '\u2715',
+      'BNB': '\u25B3',
+      'ADA': '\u25C6',
+    };
+    return icons[code] ?? '\u25CF';
+  }
+
+  /// 格式化价格显示
+  String get formattedPrice {
+    if (price >= 1000) return price.toStringAsFixed(2);
+    if (price >= 1) return price.toStringAsFixed(4);
+    return price.toStringAsFixed(6);
+  }
+
+  /// 格式化涨跌幅
+  String get formattedChange {
+    final prefix = change24h >= 0 ? '+' : '';
+    return '$prefix${change24h.toStringAsFixed(2)}%';
+  }
+
+  /// 是否上涨
+  bool get isUp => change24h >= 0;
+
+  /// 是否为实时价格
+  bool get isRealtime => priceType == 1;
+}