feat: 添加随机内容模块并优化安全配置

新增Nonsense相关实体、DTO、Repository、Service和Controller，实现随机内容的CRUD功能
优化CORS和安全配置，增加更精细的权限控制和错误处理
移除Article和Message中不必要的验证注解，调整部分API的权限要求

src/main/java/com/qf/myafterprojecy/pojo/Message.java

@@ -8,7 +8,6 @@ import java.util.Date;
 public class Message {
     @Id
     @GeneratedValue(strategy = GenerationType.IDENTITY)
-
     @Column(name = "messageid")
     private Integer messageid;
 
@@ -21,6 +20,9 @@ public class Message {
     @Column(name = "content", columnDefinition = "text")
     private String content;
 
+    @Column(name = "messageimg")
+    private String messageimg;
+
     @Temporal(TemporalType.TIMESTAMP)
     @Column(name = "created_at")
     private Date createdAt;
@@ -37,6 +39,7 @@ public class Message {
     @Column(name = "likes")
     private Integer likes; // 点赞数
 
+    
     public Integer getLikes() {
         return likes;
     }
@@ -108,4 +111,12 @@ public class Message {
     public void setArticleid(Integer articleid) {
         this.articleid = articleid;
     }
+
+    public String getMessageimg() {
+        return messageimg;
+    }
+
+    public void setMessageimg(String messageimg) {
+        this.messageimg = messageimg;
+    }
 }