Add debugging to action handling

- Add debug logging to track received actions
- Debug action processing flow
- Identify why reset_template action is not being processed

admin/setup_mvp.php

@@ -36,6 +36,7 @@ $form = new Form($db);
 
 // Handle form submission
 $action = GETPOST('action', 'alpha');
+error_log("DeclarationTVA: Action received: " . $action);
 if ($action == 'update_mappings') {
     $ca3_definitions = $config->getCA3LineDefinitions();
     $updated_count = 0;