💄 style(word-preview): 优化图片悬停效果样式

- 使用 bg-black/0 和 bg-black/20 替代 bg-black bg-opacity-0 和 bg-opacity-20 以简化背景透明度语法

src/client/admin-shadcn/pages/WordPreview.tsx

@@ -731,7 +731,7 @@ export default function WordPreview() {
                             {imageName}
                           </p>
                         </div>
-                        <div className="absolute inset-0 bg-black bg-opacity-0 group-hover:bg-opacity-20 transition-opacity rounded-lg flex items-center justify-center">
+                        <div className="absolute inset-0 bg-black/0 group-hover:bg-black/20 transition-opacity rounded-lg flex items-center justify-center">
                           <ZoomIn className="h-6 w-6 text-white opacity-0 group-hover:opacity-100 transition-opacity" />
                         </div>
                       </div>