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.

templates/parts/user-home/panels-core.php

@@ -136,8 +136,8 @@ extract($args, EXTR_SKIP); // phpcs:ignore WordPress.PHP.DontExtract.extract_ext
 						<?php
 						$product_page = max(1, isset($_GET['product_page']) ? (int) $_GET['product_page'] : 1);
 						$product_view = ['items' => [], 'total' => 0, 'max_pages' => 0];
-						if (class_exists('AKSRT_Shop')) {
-							$product_view = AKSRT_Shop::get_instance()->get_store_products((int) $user_id, $product_page, (int) $per_page);
+						if (class_exists('\AKSRT\Shop\Shop')) {
+							$product_view = \AKSRT\Shop\Shop::get_instance()->get_store_products((int) $user_id, $product_page, (int) $per_page);
 						}
 						$product_items = is_array($product_view['items'] ?? null) ? $product_view['items'] : [];
 						$product_max_pages = (int) ($product_view['max_pages'] ?? 0);