feat: 添加K线图功能 - interactive_chart + 多币种切换 + 技术指标(MA/EMA/BOLL/VOL)

flutter_monisuo/lib/models/candle.dart

@@ -0,0 +1,38 @@
+/// K 线数据模型
+class Candle {
+  final int timestamp; // 毫秒时间戳
+  final double open;
+  final double high;
+  final double low;
+  final double close;
+  final double volume;
+
+  const Candle({
+    required this.timestamp,
+    required this.open,
+    required this.high,
+    required this.low,
+    required this.close,
+    required this.volume,
+  });
+
+  factory Candle.fromJson(Map<String, dynamic> json) {
+    return Candle(
+      timestamp: json['timestamp'] as int? ?? json['time'] as int? ?? 0,
+      open: (json['open'] as num?)?.toDouble() ?? 0,
+      high: (json['high'] as num?)?.toDouble() ?? 0,
+      low: (json['low'] as num?)?.toDouble() ?? 0,
+      close: (json['close'] as num?)?.toDouble() ?? 0,
+      volume: (json['volume'] as num?)?.toDouble() ?? 0,
+    );
+  }
+
+  Map<String, dynamic> toJson() => {
+        'timestamp': timestamp,
+        'open': open,
+        'high': high,
+        'low': low,
+        'close': close,
+        'volume': volume,
+      };
+}