Refactor invoice PDF generation and VAT validation

- Updated PDF template to display a fixed software code instead of "SOFTWARE".
- Changed VAT label to include tax label dynamically and set to 0% for certain conditions.
- Enhanced JavaScript for VAT number validation with asynchronous checks against the VIES database.
- Implemented debounce for VAT number input to optimize validation calls.
- Updated country settings to include country codes for VAT validation.
- Modified email sending functions in webhook handlers to use dynamic attachment names for invoices.

assets/functions.php

@@ -1735,7 +1735,8 @@ function getProfile($profile, $permission){
         'software_download' => 'R',
         'software_available' => 'R',
         'history' => 'RU',
-        'payment' => 'RU'
+        'payment' => 'RU',
+        'vat_check' => 'RU'
     ];
 
     // 1. Check if basic_permission_level is 4 (System-admin+) - always allow
@@ -5725,7 +5726,7 @@ function generateSoftwareInvoice($invoice_data, $order_id, $language = 'US') {
     $lbl_quantity = $translations['quantity'] ?? 'Quantity';
     $lbl_price = $translations['price'] ?? 'Price';
     $lbl_subtotal = $translations['subtotal'] ?? 'Subtotal';
-    $lbl_tax = $translations['tax'] ?? 'Tax';
+    $lbl_tax = $translations['tax'] ?? 'Vat';
     $lbl_shipping = $translations['shipping'] ?? 'Shipping';
     $lbl_discount = $translations['discount'] ?? 'Discount';
     $lbl_total = $translations['total'] ?? 'Total';
@@ -5865,7 +5866,8 @@ function generateCountriesFile($token){
                 $countries[$tax['id']] = [
                     'country' => $tax['country'] ?? '',
                     'taxes' => $tax['rate'] ?? 0,
-                    'eu' => $tax['eu'] ?? 0
+                    'eu' => $tax['eu'] ?? 0,
+                    'country_code' => $tax['country_code'] ?? ''
                 ];
             }
 
@@ -5875,7 +5877,7 @@ function generateCountriesFile($token){
             $fileContent .= "// Generated on: " . date('Y-m-d H:i:s') . "\n\n";
             $fileContent .= "\$countries = [\n";
             foreach($countries as $id => $data){
-                $fileContent .= "    " . $id . " => ['country' => '" . addslashes($data['country']) . "', 'taxes' => " . $data['taxes'] . ",'eu' => " . $data['eu'] . "],\n";
+                $fileContent .= "    " . $id . " => ['country' => '" . addslashes($data['country']) . "', 'taxes' => " . $data['taxes'] . ",'eu' => " . $data['eu'] . ", 'country_code' => '" . addslashes($data['country_code']) . "'],\n";
             }
             $fileContent .= "];\n";