PayTech (Intech) - WHMCS Gateway (Third Party Redirect + IPN)

Files:
- modules/gateways/intechpaytech.php
- modules/gateways/callback/intechpaytech.php

Install:
1) Upload intechpaytech.php to /path/to/whmcs/modules/gateways/
2) Upload callback/intechpaytech.php to /path/to/whmcs/modules/gateways/callback/
3) In WHMCS Admin: Setup > Payments > Payment Gateways (Apps & Integrations)
   Activate "PayTech (Intech) - Redirect Checkout"
4) Configure: API Key, API Secret, environment, target_payment, popup mode.

Test:
- Create an invoice in WHMCS
- Open invoice, select this gateway, click Pay Now
- PayTech checkout opens (popup or redirect)
- Complete payment in sandbox/test
- PayTech sends IPN to /modules/gateways/callback/intechpaytech.php
- Invoice should be marked Paid if type_event=sale_complete

Troubleshooting:
- Enable "Debug Log" to log API responses
- Check Utilities > Logs > Gateway Log
- Make sure your WHMCS base URL is HTTPS accessible from PayTech (IPN requires HTTPS)
