v0.11.1 — frosted-glass selection label

Give the selection label a frosted-glass background.

• The "select all / N selected" label no longer paints an opaque block: its background is now the panel surface at 80% opacity with its own saturation + blur (following the panel blur setting) and a matching 12px fade on the right edge.
• Overflowing action buttons sliding underneath now show as a soft frosted blur instead of being hidden by a solid strip; the label stays readable in both flat and glass panel styles.

全选区域改为毛玻璃底色。

• 「全选 / 已选 N 段」不再画不透明色块：底色改为面板表面色的 80% 透明度，并叠加饱和度与模糊（跟随面板模糊度设置），右缘保留同色 12px 渐隐。
• 溢出滑到标签下方的操作按钮现在会被柔和的毛玻璃虚化，而不是被纯色条完全盖住；纯色扁平与毛玻璃两种面板样式下文字都保持可读。