add optional prefix to url

web/templates/login.html

@@ -8,7 +8,7 @@
   {{if .error}}
   <div class="bg-red-900/50 border border-red-700 text-red-200 rounded p-3 mb-4">{{.error}}</div>
   {{end}}
-  <form method="POST" action="/editor/login" class="space-y-4">
+  <form method="POST" action="{{url "/editor/login"}}" class="space-y-4">
     <input type="hidden" name="csrf_token" value="{{.csrf_token}}" />
     <div>
       <label class="block text-sm text-gray-300 mb-1" for="username">Username or Email</label>