fix: courseFile属性名错误

src/main/java/nju/seec/helper/entity/CourseFile.java

@@ -33,5 +33,5 @@ public class CourseFile {
 
     @Column(name = "create_at", nullable = false, updatable = false)
     @CreationTimestamp
-    private LocalDateTime creatAt;
+    private LocalDateTime createAt;
 }

src/main/java/nju/seec/helper/vo/CourseFileVO.java

@@ -15,13 +15,13 @@ public class CourseFileVO {
     private Long courseId;
     private Long teacherId;
     private String fileName;
-    private LocalDateTime creatAt;
+    private LocalDateTime createAt;
 
     public CourseFileVO(@NonNull CourseFile courseFile) {
         this.id = courseFile.getId();
         this.courseId = courseFile.getCourseId();
         this.teacherId = courseFile.getTeacherId();
         this.fileName = courseFile.getFileName();
-        this.creatAt = courseFile.getCreatAt();
+        this.createAt = courseFile.getCreateAt();
     }
 }