Results feature polish: badges, contrast, Avg/Best separation

The Results feature could use some UI polish for readability and quick scanning.

## Todo
- Add PR / NR / WR badges
- Fix color contrast (especially in dark mode)
- Make the Avg and Best columns more visually distinct
- ideas: wider cells, a vertical separator line between solve times and Avg/Best, or stronger header styling

## Notes
- Goal: make it easier to scan results at a glance without losing legibility in dark mode.

首先定位 Results 功能的 UI 入口和现有样式，然后检查结果表在浅色和深色模式下的显示效果。完成标准是 PR、NR 和 WR 徽章均已显示，深色模式下的对比度清晰易读，并且 Avg 和 Best 列在不降低可读性的情况下具有明显的视觉区分。

由索引模型根据 Issue 内容生成。