feat(mobile-app): 使用 CustomPaint 绘制跑步火柴人动画

替换 Lottie 动画为自定义绘制的跑步火柴人:
- 使用 CustomPaint 绘制火柴人形状
- 添加腿部和手臂摆动动画
- 添加速度线效果
- 当前用户显示金色，其他用户显示棕色
- 移除 lottie 依赖

🤖 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

@@ -1,5 +1,4 @@
 import 'package:flutter/material.dart';
-import 'package:lottie/lottie.dart';
 
 /// 火柴人排名数据模型
 class StickmanRankingData {
@@ -267,14 +266,11 @@ class _StickmanRaceWidgetState extends State<StickmanRaceWidget>
               const SizedBox(height: 2),
 
               // 火柴人动画
-              SizedBox(
-                width: 40,
-                height: 50,
-                child: Lottie.asset(
-                  'assets/lottie/stickman_running.json',
-                  fit: BoxFit.contain,
-                  repeat: true,
-                ),
+              RunningStickman(
+                size: 36,
+                color: data.isCurrentUser
+                    ? const Color(0xFFD4AF37)
+                    : const Color(0xFF5D4037),
               ),
 
               // 昵称标签
@@ -592,3 +588,202 @@ class _TrackPainter extends CustomPainter {
   @override
   bool shouldRepaint(covariant CustomPainter oldDelegate) => false;
 }
+
+/// 跑步火柴人动画组件
+class RunningStickman extends StatefulWidget {
+  final double size;
+  final Color color;
+
+  const RunningStickman({
+    super.key,
+    this.size = 40,
+    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,
+          ),
+        );
+      },
+    );
+  }
+}
+
+/// 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;
+  }
+}