feat(mobile-app): 使用 Lottie 动画替换火柴人 CustomPaint 实现

- 用 Lottie.asset 加载 stickman_runner.json 替换手动绘制的火柴人
- 使用 ColorFiltered 保持颜色自定义功能（当前用户金色，其他用户棕色）
- 修复火柴人到达100%时无法到达红旗位置的问题
- 代码从约200行精简到约30行，动画效果更流畅

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

frontend/mobile-app/lib/features/authorization/presentation/widgets/stickman_race_widget.dart

@@ -1,4 +1,5 @@
 import 'package:flutter/material.dart';
+import 'package:lottie/lottie.dart';
 
 /// 火柴人排名数据模型
 class StickmanRankingData {
@@ -230,10 +231,13 @@ class _StickmanRaceWidgetState extends State<StickmanRaceWidget>
         // 添加上下弹跳效果
         final bounce = _bounceController.value * 3;
 
-        // 计算可用宽度：屏幕宽度 - 页面padding(32) - 容器padding(32) - 终点区域(60) - 火柴人宽度(60)
+        // 计算可用宽度：屏幕宽度 - 页面padding(32) - 容器padding(32) - 红旗区域(40) - 火柴人宽度一半(30)
+        // 让火柴人在100%时正好到达红旗位置
         final screenWidth = MediaQuery.of(context).size.width;
         final containerWidth = screenWidth - 32 - 32; // 页面padding + 容器padding
-        final availableWidth = containerWidth - 60 - 60; // 终点区域 - 火柴人宽度
+        final stickmanHalfWidth = 30.0; // 火柴人宽度的一半，用于居中对齐
+        final flagAreaWidth = 40.0; // 红旗区域宽度（红旗在right:8位置，图标24+边距）
+        final availableWidth = containerWidth - flagAreaWidth - stickmanHalfWidth;
         final leftPosition = availableWidth * horizontalProgress;
 
         return Positioned(
@@ -587,8 +591,8 @@ class _TrackPainter extends CustomPainter {
   bool shouldRepaint(covariant CustomPainter oldDelegate) => false;
 }
 
-/// 跑步火柴人动画组件
-class RunningStickman extends StatefulWidget {
+/// 跑步火柴人动画组件 - 使用 Lottie 动画
+class RunningStickman extends StatelessWidget {
   final double size;
   final Color color;
 
@@ -598,190 +602,22 @@ class RunningStickman extends StatefulWidget {
     this.color = Colors.black,
   });
 
-  @override
-  State<RunningStickman> createState() => _RunningStickmanState();
-}
-
-class _RunningStickmanState extends State<RunningStickman>
-    with SingleTickerProviderStateMixin {
-  late AnimationController _controller;
-
-  @override
-  void initState() {
-    super.initState();
-    _controller = AnimationController(
-      duration: const Duration(milliseconds: 400),
-      vsync: this,
-    )..repeat();
-  }
-
-  @override
-  void dispose() {
-    _controller.dispose();
-    super.dispose();
-  }
-
   @override
   Widget build(BuildContext context) {
-    return AnimatedBuilder(
-      animation: _controller,
-      builder: (context, child) {
-        return CustomPaint(
-          size: Size(widget.size, widget.size * 1.2),
-          painter: _RunningStickmanPainter(
-            progress: _controller.value,
-            color: widget.color,
-          ),
-        );
-      },
+    return SizedBox(
+      width: size,
+      height: size * 1.2,
+      child: ColorFiltered(
+        colorFilter: ColorFilter.mode(
+          color,
+          BlendMode.srcIn,
+        ),
+        child: Lottie.asset(
+          'assets/lottie/stickman_runner.json',
+          fit: BoxFit.contain,
+          repeat: true,
+        ),
+      ),
     );
   }
 }
-
-/// 跑步火柴人绘制器
-class _RunningStickmanPainter extends CustomPainter {
-  final double progress;
-  final Color color;
-
-  _RunningStickmanPainter({
-    required this.progress,
-    required this.color,
-  });
-
-  @override
-  void paint(Canvas canvas, Size size) {
-    final paint = Paint()
-      ..color = color
-      ..strokeWidth = size.width * 0.08
-      ..strokeCap = StrokeCap.round
-      ..style = PaintingStyle.stroke;
-
-    final fillPaint = Paint()
-      ..color = color
-      ..style = PaintingStyle.fill;
-
-    // 尺寸计算
-    final centerX = size.width * 0.5;
-    final headRadius = size.width * 0.18;
-    final headY = size.height * 0.15;
-
-    // 身体各部位位置
-    final neckY = headY + headRadius;
-    final shoulderY = size.height * 0.35;
-    final hipY = size.height * 0.55;
-    final bodyX = centerX;
-
-    // 动画相位 (0-1 循环)
-    final phase = progress * 2 * 3.14159;
-
-    // 腿部摆动幅度
-    final legSwing = size.width * 0.35 * (phase < 3.14159 ?
-        (phase / 3.14159) * 2 - 1 :
-        1 - ((phase - 3.14159) / 3.14159) * 2);
-
-    // 手臂摆动（与腿相反）
-    final armSwing = -legSwing * 0.8;
-
-    // 绘制头部
-    canvas.drawCircle(
-      Offset(centerX, headY),
-      headRadius,
-      fillPaint,
-    );
-
-    // 绘制身体
-    canvas.drawLine(
-      Offset(bodyX, neckY),
-      Offset(bodyX, hipY),
-      paint,
-    );
-
-    // 绘制速度线（在身体左侧）
-    final speedLinePaint = Paint()
-      ..color = color
-      ..strokeWidth = size.width * 0.05
-      ..strokeCap = StrokeCap.round;
-
-    for (int i = 0; i < 3; i++) {
-      final lineY = shoulderY + i * size.height * 0.08;
-      final lineStartX = centerX - size.width * 0.5;
-      final lineEndX = lineStartX + size.width * 0.2;
-      canvas.drawLine(
-        Offset(lineStartX, lineY),
-        Offset(lineEndX, lineY),
-        speedLinePaint,
-      );
-    }
-
-    // 绘制手臂
-    // 后手臂
-    final backArmEndX = bodyX - size.width * 0.25 + armSwing * 0.5;
-    final backArmEndY = shoulderY + size.height * 0.15;
-    canvas.drawLine(
-      Offset(bodyX, shoulderY),
-      Offset(backArmEndX, backArmEndY),
-      paint,
-    );
-    // 后手臂前臂
-    canvas.drawLine(
-      Offset(backArmEndX, backArmEndY),
-      Offset(backArmEndX + size.width * 0.15, backArmEndY - size.height * 0.1),
-      paint,
-    );
-
-    // 前手臂
-    final frontArmEndX = bodyX + size.width * 0.2 - armSwing * 0.5;
-    final frontArmEndY = shoulderY + size.height * 0.12;
-    canvas.drawLine(
-      Offset(bodyX, shoulderY),
-      Offset(frontArmEndX, frontArmEndY),
-      paint,
-    );
-    // 前手臂前臂
-    canvas.drawLine(
-      Offset(frontArmEndX, frontArmEndY),
-      Offset(frontArmEndX + size.width * 0.1, frontArmEndY - size.height * 0.08),
-      paint,
-    );
-
-    // 绘制腿部
-    final footY = size.height * 0.95;
-
-    // 后腿
-    final backKneeX = bodyX - size.width * 0.1 - legSwing * 0.3;
-    final backKneeY = hipY + size.height * 0.2;
-    final backFootX = bodyX - size.width * 0.3 + legSwing * 0.5;
-
-    canvas.drawLine(
-      Offset(bodyX, hipY),
-      Offset(backKneeX, backKneeY),
-      paint,
-    );
-    canvas.drawLine(
-      Offset(backKneeX, backKneeY),
-      Offset(backFootX, footY),
-      paint,
-    );
-
-    // 前腿
-    final frontKneeX = bodyX + size.width * 0.15 + legSwing * 0.3;
-    final frontKneeY = hipY + size.height * 0.18;
-    final frontFootX = bodyX + size.width * 0.35 - legSwing * 0.5;
-
-    canvas.drawLine(
-      Offset(bodyX, hipY),
-      Offset(frontKneeX, frontKneeY),
-      paint,
-    );
-    canvas.drawLine(
-      Offset(frontKneeX, frontKneeY),
-      Offset(frontFootX, footY),
-      paint,
-    );
-  }
-
-  @override
-  bool shouldRepaint(covariant _RunningStickmanPainter oldDelegate) {
-    return oldDelegate.progress != progress;
-  }
-}