fix: harden DynDNS recovery and publish v1.5.1

internal/web/templates/layout.html

@@ -6,8 +6,8 @@
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <meta name="color-scheme" content="light">
   <title>{{.Title}} · DNS Control</title>
-  <link rel="stylesheet" href="/static/styles.css?v=features-29">
-  <script src="/static/app.js?v=features-29" defer></script>
+  <link rel="stylesheet" href="/static/styles.css?v=features-30">
+  <script src="/static/app.js?v=features-30" defer></script>
 </head>
 <body class="page-{{.Page}}">
   <a class="skip-link" href="#main">Zum Inhalt springen</a>