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>

app/Support/Qr/QrCoverImageSpec.php

@@ -0,0 +1,20 @@
+<?php
+
+namespace App\Support\Qr;
+
+class QrCoverImageSpec
+{
+    /** Wide hero banners (business, church, event, itinerary, menu, shop). */
+    public const BANNER = '1920×1080 px (16:9 landscape)';
+
+    /** Book product cover on the landing page. */
+    public const BOOK = '800×1067 px (3:4 portrait)';
+
+    public static function label(string $variant = 'banner'): string
+    {
+        return match ($variant) {
+            'book' => self::BOOK,
+            default => self::BANNER,
+        };
+    }
+}