feat: add signed PostgreSQL release updates

oa-backend/src/main/java/com/kaidi/oa/domain/CollabDoc.java

@@ -5,7 +5,6 @@ import jakarta.persistence.Entity;
 import jakarta.persistence.GeneratedValue;
 import jakarta.persistence.GenerationType;
 import jakarta.persistence.Id;
-import jakarta.persistence.Lob;
 import jakarta.persistence.Table;
 
 import java.time.Instant;
@@ -33,19 +32,16 @@ public class CollabDoc {
 
     private String status;
 
-    @Lob
     @Column(columnDefinition = "TEXT")
     private String content;
 
     private Instant updatedAt;
 
     /** 历史版本 JSON 数组：[{version, content, savedAt, editor}]。每次更新正文前追加上一版。 */
-    @Lob
     @Column(columnDefinition = "TEXT")
     private String versionsJson;
 
     /** 评论/批注 JSON 数组：[{author, content, createdAt}]。 */
-    @Lob
     @Column(columnDefinition = "TEXT")
     private String commentsJson;