refactor(autoload): migrate theme classes to Composer PSR-4

Move 288 types from global AKSRT_* + inc/classes manual requires into
namespace AKSRT\{Domain} under src/AKSRT/, wire composer.json psr-4,
and slim bootstrap to helpers/modules/hooks only. Split multi-class
widget/gateway files, update admin contract audit paths, and document
the layout in ADR/README.

inc/helpers/aksrt-auth-ui.php

@@ -18,8 +18,8 @@ if (!function_exists('aksrt_get_auth_agreement_view')) {
         $required = true;
         $page_ref = '';
 
-        if (class_exists('AKSRT_Settings') && method_exists('AKSRT_Settings', 'user_agreement_settings')) {
-            $cfg = AKSRT_Settings::user_agreement_settings();
+        if (class_exists('\AKSRT\Settings\Settings') && method_exists('\AKSRT\Settings\Settings', 'user_agreement_settings')) {
+            $cfg = \AKSRT\Settings\Settings::user_agreement_settings();
             $enabled  = !empty($cfg['enabled']);
             $required = !empty($cfg['required']);
             $page_ref = (string) ($cfg['page'] ?? '');
@@ -61,7 +61,7 @@ if (!function_exists('aksrt_get_auth_sign_logo_html')) {
      * Shared logo block for full-page sign shell.
      */
     function aksrt_get_auth_sign_logo_html(): string {
-        $logo_url = class_exists('AKSRT_Settings') ? AKSRT_Settings::user_logo_url() : '';
+        $logo_url = class_exists('\AKSRT\Settings\Settings') ? \AKSRT\Settings\Settings::user_logo_url() : '';
         $home = home_url('/');
         $name = get_bloginfo('name');
         if ($logo_url) {