fix: log-service entity fingerprint CHAR(64) 对齐 Flyway migration

Co-Authored-By: Claude <noreply@anthropic.com>

xuqm-log-service/src/main/java/com/xuqm/log/entity/LogIssueEntity.java

@@ -14,7 +14,7 @@ public class LogIssueEntity {
     @Column(nullable = false, length = 64)
     private String appKey;
 
-    @Column(nullable = false, length = 64)
+    @Column(nullable = false, columnDefinition = "CHAR(64)")
     private String fingerprint;
 
     @Column(nullable = false, length = 32)