Expand Link app with analytics, settings, and custom domains.

Add Bitly-style branded domain support via Ladill Domains SSL API,
account analytics dashboard, settings page with default domain picker,
and fix SSO/dashboard issues from QR Plus template leftovers.

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

app/Services/CustomDomain/DnsResolver.php

@@ -0,0 +1,17 @@
+<?php
+
+namespace App\Services\CustomDomain;
+
+class DnsResolver
+{
+    /** @return array<int,string> */
+    public function aRecords(string $host): array
+    {
+        $records = @dns_get_record($host, DNS_A);
+        if (! is_array($records)) {
+            return [];
+        }
+
+        return array_values(array_filter(array_map(fn ($r) => $r['ip'] ?? null, $records)));
+    }
+}