refactor(StudyCoursePage): 优化顶部区域高度计算逻辑

使用 ResizeObserver 替代 setTimeout 监听元素尺寸变化，提高响应速度和准确性。移除不必要的延迟，并在组件卸载时取消监听，避免内存泄漏。

@@ -8,11 +8,7 @@
             <!-- 固定区域：课程封面和标签页 -->
             <div class="fixed top-0 left-0 right-0 z-10 top-wrapper bg-white">
                 <!-- 课程封面区域 -->
-                <van-image
-                    class="w-full aspect-video object-cover"
-                    :src="course?.coverImage"
-                    :alt="course?.title"
-                />
+                <van-image class="w-full aspect-video object-cover" :src="course?.coverImage" :alt="course?.title" />
                 <div class="p-4">
                     <h1 class="text-black text-xl font-bold mb-2">{{ course?.title }}</h1>
                     <div class="flex items-center text-gray-500 text-sm">
@@ -38,7 +34,8 @@
             </div>
 
             <!-- 滚动区域：详情、目录和互动内容 -->
-            <div class="overflow-y-auto flex-1" :style="{paddingTop: topWrapperHeight, height: 'calc(100vh - ' + topWrapperHeight + ')'}">
+            <div class="overflow-y-auto flex-1"
+                :style="{ paddingTop: topWrapperHeight, height: 'calc(100vh - ' + topWrapperHeight + ')' }">
                 <!-- 详情区域 -->
                 <div id="detail" class="py-4 px-4">
                     <div class="text-gray-700 text-sm leading-relaxed" v-html="course?.description"></div>
@@ -50,8 +47,12 @@
                 <!-- 目录区域 -->
                 <div id="catalog" class="py-4">
                     <div class="space-y-4">
-                        <div v-for="(lesson, index) in course?.lessons" :key="index" @click="router.push(`/studyDetail/${lesson.id}`)" class="bg-white p-4 cursor-pointer hover:bg-gray-50 transition-colors border-b border-gray-200 relative">
-                            <div v-if="lesson.progress > 0 && lesson.progress < 100" class="absolute top-2 right-2 px-2 py-1 bg-green-100 text-green-600 text-xs rounded">上次看到</div>
+                        <div v-for="(lesson, index) in course?.lessons" :key="index"
+                            @click="router.push(`/studyDetail/${lesson.id}`)"
+                            class="bg-white p-4 cursor-pointer hover:bg-gray-50 transition-colors border-b border-gray-200 relative">
+                            <div v-if="lesson.progress > 0 && lesson.progress < 100"
+                                class="absolute top-2 right-2 px-2 py-1 bg-green-100 text-green-600 text-xs rounded">
+                                上次看到</div>
                             <div class="text-black text-base font-medium mb-2">{{ lesson.title }}</div>
                             <div class="flex items-center text-sm text-gray-500">
                                 <span>视频</span>&nbsp;
@@ -105,17 +106,21 @@ const topWrapperHeight = ref(0);
 
 // 计算topWrapperHeight的函数
 const updateTopWrapperHeight = () => {
-    setTimeout(() => {
-        nextTick(() => {
-            const topWrapper = document.querySelector('.top-wrapper');
-            if (topWrapper) {
-                // 确保在DOM更新后获取正确的高度
-                requestAnimationFrame(() => {
-                    topWrapperHeight.value = `${topWrapper.offsetHeight}px`;
-                });
-            }
-        });
-    }, 500);
+    nextTick(() => {
+        const topWrapper = document.querySelector('.top-wrapper');
+        if (topWrapper) {
+            // 使用 ResizeObserver 监听元素尺寸变化
+            const resizeObserver = new ResizeObserver(() => {
+                topWrapperHeight.value = `${topWrapper.offsetHeight}px`;
+            });
+            resizeObserver.observe(topWrapper);
+
+            // 组件卸载时取消监听
+            onUnmounted(() => {
+                resizeObserver.disconnect();
+            });
+        }
+    });
 };
 
 // 初始化时计算topWrapperHeight