Add GPT-6 Luna model option

administrator/components/com_testquestions/sql/updates/mysql/1.43.6.sql

@@ -0,0 +1 @@
+-- No database changes required for version 1.43.6.

administrator/components/com_testquestions/src/Service/AiService.php

@@ -16,6 +16,7 @@ class AiService
                 'gpt-5.6-luna' => 'GPT-5.6 Luna',
                 'gpt-5.6-terra' => 'GPT-5.6 Terra',
                 'gpt-5.6-sol' => 'GPT-5.6 Sol',
+                'gpt-6-luna' => 'GPT-6 Luna',
             ],
             'grok' => [
                 'grok-4.7' => 'Grok 4.7',
@@ -155,6 +156,7 @@ class AiService
             'gpt-5.6-luna' => [0.20, 0.02, 1.20, 0.25],
             'gpt-5.6-terra' => [2.00, 0.20, 12.00, 2.50],
             'gpt-5.6-sol' => [4.00, 0.40, 20.00, 5.00],
+            'gpt-6-luna' => [0.10, 0.01, 0.50, 0.125],
         ];
     }