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.

src/AKSRT/Admin/Schema/SchemaShop.php

@@ -0,0 +1,28 @@
+<?php
+/**
+ * @package AKSRT
+ */
+
+namespace AKSRT\Admin\Schema;
+
+defined('ABSPATH') || exit;
+
+class SchemaShop {
+
+    public static function build(): array {
+        return [
+            'key'      => 'shop',
+            'title'    => '商城&商品',
+            'version'  => '1.0.0',
+            'sections' => [
+                'basic'            => SchemaShopBasic::build(),
+                'list'             => SchemaShopList::build(),
+                'contact'          => SchemaShopContact::build(),
+                'single'           => SchemaShopSingle::build(),
+                'product-defaults' => SchemaShopProductDefaults::build(),
+                'shipping-config'  => SchemaShopShippingConfig::build(),
+                'timing'           => SchemaShopTiming::build(),
+            ],
+        ];
+    }
+}