Initial Ladill Give extraction — online giving pages at give.ladill.com.

Donation checkout via Ladill Pay (9% fee), church/giving QR pages, SSO, and platform scan forwarding.

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

config/billing.php

@@ -0,0 +1,8 @@
+<?php
+
+return [
+    'api_url' => env('BILLING_API_URL', 'https://ladill.com/api/billing'),
+    'api_key' => env('BILLING_API_KEY_GIVE'),
+    'service' => 'give',
+    'platform_settings_connection' => env('BILLING_PLATFORM_SETTINGS_CONNECTION', 'platform'),
+];