feat: configure integration secret and update seeder for Telepagos integration

app/Domains/Integration/Casts/EncryptedIntegrationData.php

@@ -11,10 +11,10 @@ class EncryptedIntegrationData implements CastsAttributes
 {
     protected function getEncrypter(): Encrypter
     {
-        $secret = env('INTEGRATION_SECRET');
+        $secret = config('services.integrations.secret');
         
         if (empty($secret)) {
-            throw new Exception('INTEGRATION_SECRET is not set in the environment.');
+            throw new Exception('The integrations secret is not configured.');
         }
 
         // Laravel encrypter requires a key of exact length. Typically 32 bytes for AES-256-CBC.