fix(teacher): 修复学生页面点评状态的可选链判断

@@ -2,7 +2,7 @@
  * @Author: hookehuyr hookehuyr@gmail.com
  * @Date: 2025-06-19 17:12:19
  * @LastEditors: hookehuyr hookehuyr@gmail.com
- * @LastEditTime: 2025-10-28 11:10:00
+ * @LastEditTime: 2025-10-28 11:13:52
  * @FilePath: /mlaj/src/views/teacher/studentPage.vue
  * @Description: 学生详情页面
 -->
@@ -259,13 +259,13 @@
             <div class="flex items-center cursor-pointer" @click="openCommentPopup(post)">
               <van-icon
                 name="comment-o"
-                :color="post.is_feedback ? '#10b981' : '#999'"
+                :color="post?.is_feedback ? '#10b981' : '#999'"
                 size="19"
                 class="mr-1"
                 style="margin-top: 0.2rem;"
               />
-              <span class="text-sm" :class="post.is_feedback ? 'text-green-600' : 'text-gray-500'">
-                {{ post.is_feedback ? '已点评' : '待点评' }}
+              <span class="text-sm" :class="post?.is_feedback ? 'text-green-600' : 'text-gray-500'">
+                {{ post?.is_feedback ? '已点评' : '待点评' }}
               </span>
             </div>
           </div>
@@ -301,7 +301,7 @@
           <!-- 评分 -->
           <div class="mb-4">
             <div class="text-sm text-gray-600 mb-2">评分</div>
-            <van-rate v-model="commentForm.score" :size="24" color="#ffd21e" void-color="#eee" :readonly="currentCommentPost.is_feedback" />
+            <van-rate v-model="commentForm.score" :size="24" color="#ffd21e" void-color="#eee" :readonly="currentCommentPost?.is_feedback" />
           </div>
 
           <!-- 点评内容 -->
@@ -316,12 +316,12 @@
               show-word-limit
               :border="false"
               class="bg-gray-50 rounded-lg"
-              :readonly="currentCommentPost.is_feedback"
+              :readonly="currentCommentPost?.is_feedback"
             />
           </div>
 
           <!-- 操作按钮 -->
-          <div v-if="!currentCommentPost.is_feedback" class="flex gap-3">
+          <div v-if="!currentCommentPost?.is_feedback" class="flex gap-3">
             <van-button
               block
               type="default"