feat: add downstream domain fix plugin

menu.php

@@ -0,0 +1,13 @@
+<?php
+return [
+    [
+        'name' => '修复推送域名',
+        'url' => 'DownstreamDomainFix://AdminIndex/index',
+        'custom' => 0,
+        'lang' => [
+            'chinese' => '修复推送域名',
+            'chinese_tw' => '修復推送域名',
+            'english' => 'Fix Domain',
+        ],
+    ],
+];