MRBS 1.12.2 等保2.0二级整改完整提交

包含：登录失败锁定、90天密码有效期、30分钟会话超时、
强制改密、登录审计日志、屏幕水印、企业背景图、
备案信息固定底部、favicon、JS空集合保护、
会话过期体验优化（403 JSON）、display_errors 关闭、
固定 key 根治 Integrity check failed 等全部改动

注意：config.inc.php/.htaccess/.user.ini 含敏感信息，
通过 .gitignore 排除，勿推送到公开仓库。

upgrade/25/mysql.sql

@@ -0,0 +1,10 @@
+# Fixes a mistake in the previous upgrade.  If we've got an individual member of a
+# series that has been modified, ie has entry_type=2, then the sequence number 
+# cannot be 0.   We will set it to 1.
+
+ALTER TABLE %DB_TBL_PREFIX%entry ADD COLUMN saved_ts DATETIME;
+UPDATE %DB_TBL_PREFIX%entry SET saved_ts=timestamp;
+UPDATE %DB_TBL_PREFIX%entry 
+  SET ical_sequence=1 WHERE ical_sequence=0 AND entry_type=2;
+UPDATE %DB_TBL_PREFIX%entry SET timestamp=saved_ts;
+ALTER TABLE %DB_TBL_PREFIX%entry DROP COLUMN saved_ts;