feat(检查页面): 添加作业描述显示区域

在检查页面中添加作业描述显示区域，包括样式和空状态处理

 <!--
   * @Date: 2025-05-29 15:34:17
  * @LastEditors: hookehuyr hookehuyr@gmail.com
- * @LastEditTime: 2026-01-18 21:57:29
+ * @LastEditTime: 2026-01-18 22:09:36
  * @FilePath: /mlaj/src/views/checkin/IndexCheckInPage.vue
   * @Description: 文件描述
 -->
@@ -25,6 +25,15 @@
 
       <!-- 可滚动的内容区域 -->
       <div class="scrollable-content">
+        <!-- 作业描述 -->
+        <div v-if="taskDetail.note" class="text-wrapper">
+          <div class="text-header">作业描述</div>
+          <div class="task-note-box">
+            <div v-if="taskDetail.note" class="task-note-text" v-html="taskDetail.note"></div>
+            <div v-else class="task-note-empty">暂无作业描述</div>
+          </div>
+        </div>
+
         <div v-if="taskDetail.task_type === 'count'" class="text-wrapper" style="padding-bottom: 0;">
           <div class="text-header">我的{{ dynamicFieldText }}</div>
           <div style="margin: 0.5rem 0;">
@@ -891,6 +900,37 @@ onActivated(async () => {
     font-size: 1.15rem;
   }
 
+  .task-note-box {
+    background-color: #fff;
+    margin-top: 1rem;
+    border-radius: 12px;
+    padding: 0.75rem 1rem;
+  }
+
+  .task-note-text {
+    color: #333;
+    font-size: 0.9rem;
+    line-height: 1.6;
+    word-break: break-word;
+
+    p {
+      margin: 0.4rem 0;
+    }
+
+    img {
+      max-width: 100%;
+      height: auto;
+      border-radius: 8px;
+      display: block;
+      margin: 0.5rem 0;
+    }
+  }
+
+  .task-note-empty {
+    color: #9ca3af;
+    font-size: 0.9rem;
+  }
+
   .grade-percentage-main {
     padding: 0.75rem 1rem;
   }