refactor(UI): 移除卡片图片并添加骨架屏动画

移除多个页面中的默认卡片图片以简化UI
在评分图表区域添加骨架屏加载动画，提升用户体验

styles.css

@@ -128,4 +128,31 @@ body {
 .age-rating svg {
     width: 20px;
     height: 20px;
+}
+
+/* 骨架屏加载动画 */
+.skeleton-chart {
+    width: 400px;
+    height: 200px;
+    background: #f0f0f0;
+    border-radius: 4px;
+    position: relative;
+    overflow: hidden;
+}
+
+@keyframes shimmer {
+    0% { background-position: -468px 0 }
+    100% { background-position: 468px 0 }
+}
+
+.skeleton-chart::after {
+    content: "";
+    position: absolute;
+    top: 0;
+    right: 0;
+    bottom: 0;
+    left: 0;
+    transform: translateX(-100%);
+    background: linear-gradient(90deg, rgba(255,255,255,0) 0%, rgba(255,255,255,0.2) 20%, rgba(255,255,255,0.5) 60%, rgba(255,255,255,0) 100%);
+    animation: shimmer 2s infinite;
 }