Use + icon buttons on mobile dashboards.

Sync mobile-header-btn partials, mobile x-btn.create, and update dashboard header actions for consistent mobile FABs.

Co-authored-by: Cursor <cursoragent@cursor.com>

resources/views/components/domain-source-fields.blade.php

@@ -8,6 +8,7 @@
 ])
 
 @php
+    $errors = $errors ?? new \Illuminate\Support\ViewErrorBag;
     $ownedDomainHosts = collect($ownedDomains)->map(fn ($d) => (string) $d)->all();
     $oldValue = trim((string) old($fieldName, ''));
     $initialDomainSource = empty($ownedDomainHosts)