feat(mobile): 优化火柴人赛跑组件布局

- 将昵称移到左侧固定位置，与右边红旗相呼应
- 保持数量标签在火柴人上方，间距2像素

🤖 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

@@ -313,7 +313,8 @@ class _StickmanRaceWidgetState extends State<StickmanRaceWidget>
                             ),
                           ),
                         ),
-                        // 火柴人动画 - 缩小与标签的间距
+                        const SizedBox(height: 2),
+                        // 火柴人动画
                         RunningStickman(
                           size: 36,
                           color: data.isCurrentUser