Extract Ladill QR Plus as standalone app at qr.ladill.com.

Utility QR types only (URL, WiFi, link list, business, app download) with
SSO, Billing API integration, public /q resolver, and qr-plus:import for
platform migration. vCard and commerce types stay on the platform.

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

config/emaildomain.php

@@ -0,0 +1,7 @@
+<?php
+
+return [
+    // Consumer config for the shared Email-Domain verification API (§4-D).
+    'api_url' => env('EMAILDOMAIN_API_URL', 'https://ladill.com/api/email-domains'),
+    'api_key' => env('EMAILDOMAIN_API_KEY_EMAIL'),
+];