feat: add signed PostgreSQL release updates

oa-backend/src/main/java/com/kaidi/oa/domain/TechAchievement.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;
 
 /**
@@ -47,7 +47,7 @@ public class TechAchievement {
     private Long ipAssetId;
 
     /** 佐证材料清单（论文/标准/软著/检测报告…）。 */
-    @Lob
+    @Column(columnDefinition = "TEXT")
     private String evidence;
 
     /** 成果评价等级。 */