feat: add signed PostgreSQL release updates

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

@@ -6,7 +6,7 @@ import jakarta.persistence.Entity;
 import jakarta.persistence.GeneratedValue;
 import jakarta.persistence.GenerationType;
 import jakarta.persistence.Id;
-import jakarta.persistence.Lob;
+import jakarta.persistence.Column;
 import jakarta.persistence.Table;
 
 /**
@@ -30,7 +30,7 @@ public class ChronicleEvent {
 
     private String category;
 
-    @Lob
+    @Column(columnDefinition = "TEXT")
     private String description;
 
     /** 关联文档/单据（逗号分隔的引用，如 IP-2026-0001 / 合同号 / 文件名）。 */