feat(学生): 添加学生课程查询功能

- 后端添加获取学生课程列表的API路由
- 实现Course模型中的findByStudentId方法查询学生课程
- 新增学生控制器的getCourses方法处理课程请求
- 前端添加课程表格展示及刷新功能

frontend/views/student/dashboard.html

@@ -337,6 +337,39 @@
             </div>
         </div>
 
+        <!-- 我的课程表格 -->
+        <div class="card card-table mb-4" id="courses-section">
+            <div class="card-header d-flex justify-content-between align-items-center">
+                <h5 class="mb-0 fw-bold"><i class="fas fa-book me-2 text-primary"></i>我的课程</h5>
+                <button class="btn btn-sm btn-outline-primary px-3" id="refreshCourses">
+                    <i class="fas fa-sync-alt me-1"></i> 刷新
+                </button>
+            </div>
+            <div class="table-responsive">
+                <table class="table table-hover align-middle mb-0">
+                    <thead>
+                        <tr>
+                            <th>课程代码</th>
+                            <th>课程名称</th>
+                            <th>学分</th>
+                            <th>授课教师</th>
+                            <th>学期</th>
+                            <th>操作</th>
+                        </tr>
+                    </thead>
+                    <tbody id="coursesTableBody">
+                        <!-- 数据将由 JavaScript 填充 -->
+                        <tr>
+                            <td colspan="6" class="text-center py-5 text-muted">
+                                <div class="spinner-border spinner-border-sm me-2" role="status"></div>
+                                数据加载中...
+                            </td>
+                        </tr>
+                    </tbody>
+                </table>
+            </div>
+        </div>
+
         <!-- 成绩表格 -->
         <div class="card card-table" id="grades-section">
             <div class="card-header d-flex justify-content-between align-items-center">