Route SMS voice uploads through Transfer with wallet billing.

Add a service API for the Ladill SMS platform to store voice recordings in Transfer and charge monthly storage from the customer wallet.

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

config/transfer.php

@@ -6,6 +6,7 @@ return [
     */
     'service_api_keys' => array_filter([
         'webmail' => env('TRANSFER_API_KEY_WEBMAIL'),
+        'sms' => env('TRANSFER_API_KEY_SMS'),
     ]),
 
     // GHS per GB per month of retention (see qr-suite-decomposition.md §7.3).
@@ -35,4 +36,7 @@ return [
     // Legacy env keys (billing is monthly until cancelled by non-payment + grace).
     'default_retention_days' => (int) env('TRANSFER_DEFAULT_RETENTION_DAYS', 30),
     'mail_retention_days' => (int) env('TRANSFER_MAIL_RETENTION_DAYS', 30),
+
+    // Voice SMS uploads from sms.ladill.com (via platform API).
+    'sms_voice_max_upload_kb' => (int) env('TRANSFER_SMS_VOICE_MAX_UPLOAD_KB', 5120),
 ];