feat(教师表单): 重构课程选择逻辑为级联选择

将课程选择改为优先选择，驱动年级和班级的级联选择
更新API返回数据结构以支持新的级联逻辑

 /*
  * @Date: 2025-06-23 11:46:21
  * @LastEditors: hookehuyr hookehuyr@gmail.com
- * @LastEditTime: 2025-11-07 17:16:04
+ * @LastEditTime: 2025-11-10 10:56:17
  * @FilePath: /mlaj/src/api/teacher.js
  * @Description: 文件描述
  */
@@ -31,7 +31,7 @@ export const getTeacherGradeClassListAPI = (params) => fn(fetch.get(Api.TEACHER_
 
 /**
  * 获取老师查询作业参数
- * @returns {Object} data { grade_list [{id, grade_name}], class_list [{id, class_name}], group_list [{id, title, schedule_list[{id, title}]}], task_type, task_frequency }
+ * @returns {Object} data { group_list [{id, title, schedule_list[{id, title}], team_list[{id, team_name, subteam_list[{id, subteam_name}]}]}], task_type, task_frequency }
  */
 export const getTeacherFindSettingsAPI = (params) => fn(fetch.get(Api.TEACHER_FIND_SETTINGS, params))
 

@@ -133,6 +133,15 @@
 
               <!-- 选择项目 -->
               <div class="mb-6">
+                <!-- 优先选择课程，驱动后续年级与班级级联 -->
+                <div class="select-row">
+                  <div class="select-item">
+                    <van-icon name="friends-o" class="select-icon" />
+                    <span class="select-label">所在课程：</span>
+                    <span class="select-value" @click="showCoursePicker = true">{{ formData.course || '请选择课程' }}</span>
+                    <van-icon name="arrow" class="arrow-icon" @click="showCoursePicker = true" />
+                  </div>
+                </div>
                 <div class="select-row">
                   <div class="select-item">
                     <van-icon name="friends-o" class="select-icon" />
@@ -149,15 +158,8 @@
                     <van-icon name="arrow" class="arrow-icon" @click="showClassPicker = true" />
                   </div>
                 </div>
-                <div class="select-row">
-                  <div class="select-item">
-                    <van-icon name="friends-o" class="select-icon" />
-                    <span class="select-label">所在课程：</span>
-                    <span class="select-value" @click="showCoursePicker = true">{{ formData.course || '请选择课程' }}</span>
-                    <van-icon name="arrow" class="arrow-icon" @click="showCoursePicker = true" />
-                  </div>
-                </div>
-                <div class="select-row" v-if="courseChapters[formData.course]?.length">
+                <!-- 仅在完成班级选择后，允许进行课程章节选择 -->
+                <div class="select-row" v-if="formData.class_id && courseChapters[formData.course]?.length">
                   <div class="select-item">
                     <van-icon name="bookmark-o" class="select-icon" />
                     <span class="select-label">课程章节：</span>
@@ -672,6 +674,19 @@ const onEndTimeConfirm = () => {
 const onCourseSelect = (course) => {
   formData.value.course = course.name;
   formData.value.lesson_id = course.id;
+  // 重置级联选择
+  formData.value.grade = '';
+  formData.value.grade_id = '';
+  formData.value.class_name = '';
+  formData.value.class_id = '';
+  // 根据课程派生年级列表
+  grades.value = (course.team_list || []).map(team => ({
+    name: team.team_name,
+    id: String(team.id),
+    subteam_list: team.subteam_list || []
+  }));
+  // 清空班级列表，待年级选择后填充
+  classes.value = [];
   // 清空之前选择的章节
   selectedChapters.value = [];
   // 根据选择的课程更新章节数据
@@ -812,6 +827,14 @@ const confirmChapterSelection = () => {
 const onGradeSelect = (grade) => {
   formData.value.grade = grade.name;
   formData.value.grade_id = grade.id;
+  // 根据年级派生班级列表
+  classes.value = (grade.subteam_list || []).map(sub => ({
+    name: sub.subteam_name,
+    id: String(sub.id)
+  }));
+  // 清空已选择的班级，等待用户确认
+  formData.value.class_name = '';
+  formData.value.class_id = '';
   showGradePicker.value = false;
   gradeSearchValue.value = '';
 };
@@ -957,18 +980,15 @@ onMounted(async () => {
       }));
     }
 
-    grades.value = data.grade_list.map(grade => ({
-      name: grade.grade_name,
-      id: String(grade.id)
-    }));
-    classes.value = data.class_list.map(classItem => ({
-      name: classItem.class_name,
-      id: String(classItem.id)
-    }));
+    // 年级与班级不再从顶层返回，改为根据所选课程派生
+    grades.value = [];
+    classes.value = [];
+    // 课程包含章节与年级树
     courses.value = data.group_list.map(course => ({
       name: course.title,
       id: String(course.id),
-      schedule_list: course.schedule_list
+      schedule_list: course.schedule_list || [],
+      team_list: course.team_list || []
     }));
     data.group_list.forEach(course => {
       courseChapters.value[course.title] = course.schedule_list.map(chapter => ({