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/5/post.inc

@@ -0,0 +1,26 @@
+<?php
+namespace MRBS;
+
+$exists = $upgrade_handle->table_exists(_tbl('users'));
+
+/* If the table does not exist */
+if (!$exists)
+{
+  /* Then create it */
+  $cmd = "
+CREATE TABLE " . _tbl('users') . "
+(
+  /* The first four fields are required. Don't remove. */
+  id        ".$upgrade_handle->syntax_createtable_autoincrementcolumn().",
+  level     smallint DEFAULT '0' NOT NULL,  /* play safe and give no rights */
+  name      varchar(30),
+  password  varchar(40),
+  email     varchar(75),
+
+  /* The following fields are application-specific. However only int and varchar are editable. */
+
+
+  PRIMARY KEY (id)
+);";
+  $upgrade_handle->command($cmd);
+}