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。

lib/MRBS/ICalendar/RFC5545.php

@@ -0,0 +1,48 @@
+<?php
+declare(strict_types=1);
+namespace MRBS\ICalendar;
+
+use DateTimeZone;
+use MRBS\DateTime;
+use function MRBS\get_vocab;
+
+class RFC5545
+{
+  // An array which can be used to map day of the week numbers (0..6)
+  // onto days of the week as defined in RFC 5545
+  public const DAYS = ['SU', 'MO', 'TU', 'WE', 'TH', 'FR', 'SA'];
+
+
+  // Convert an RFC 5545 day to an ordinal number representing the day of the week,
+  // eg "MO" returns "1"
+  public static function convertDayToOrd($day) : int
+  {
+    $tmp = array_keys(self::DAYS, $day);
+
+    if (count($tmp) === 0)
+    {
+      throw new RFC5545Exception(
+        get_vocab('invalid_RFC5545_day', $day),
+        RFC5545Exception::INVALID_DAY
+      );
+    }
+
+    return $tmp[0];
+  }
+
+
+  // Splits a BYDAY string into its ordinal and day parts, returned as a simple array.
+  // For example "-1SU" is returned an array indexed by 'ordinal' and 'day' keys, eg
+  // array('ordinal' => -1, 'day' => 'SU');
+  public static function parseByday(string $byday) : array
+  {
+    $result = array();
+
+    $split_pos = mb_strlen($byday) -2;
+    $result['ordinal'] = (int) mb_substr($byday, 0, $split_pos);
+    $result['day'] = mb_substr($byday, $split_pos, 2);
+
+    return $result;
+  }
+
+}