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/Core/Templates.php

@@ -0,0 +1,141 @@
+<?php
+/**
+ * @package AKSRT
+ */
+
+namespace AKSRT\Core;
+
+defined('ABSPATH') || exit;
+
+class Templates {
+
+    private static $instance = null;
+
+    private function __construct() {}
+
+    public static function get_instance(): self {
+        if (null === self::$instance) {
+            self::$instance = new self();
+        }
+
+        return self::$instance;
+    }
+
+    public function init(): void {
+        add_filter('theme_page_templates', [$this, 'register_page_templates']);
+        add_filter('template_include', [$this, 'load_page_template']);
+        add_filter('template_include', [$this, 'load_taxonomy_template']);
+        add_filter('page_template_hierarchy', [$this, 'template_hierarchy']);
+        add_filter('aksrt_page_template_hierarchy', [$this, 'template_hierarchy']);
+
+        // 短代码注册统一在 Shortcodes（registry）；本类只提供 archive/profile 渲染实现。
+    }
+
+    /**
+     * Selectable page templates shown in wp-admin for the rebuilt mainline.
+     */
+    private function page_template_map(): array {
+        return [
+            'templates/pages/page-sign.php' => __('AKSRT - 登录/注册', 'aksrt'),
+            'templates/pages/page-profile.php' => __('AKSRT - 个人中心', 'aksrt'),
+            'templates/pages/page-user-home.php' => __('AKSRT - 用户主页', 'aksrt'),
+            'templates/pages/page-archives.php' => __('AKSRT - 文章归档', 'aksrt'),
+            'templates/pages/page-categories.php' => __('AKSRT - 分类汇总', 'aksrt'),
+            'templates/pages/page-newposts.php' => __('AKSRT - 最新文章', 'aksrt'),
+            'templates/pages/page-posts-navs.php' => __('AKSRT - 文章导航', 'aksrt'),
+            'templates/pages/page-friends.php' => __('AKSRT - 友情链接', 'aksrt'),
+            'templates/pages/page-orders.php' => __('AKSRT - 订单中心', 'aksrt'),
+            'templates/pages/page-revenue.php' => __('AKSRT - 收益中心', 'aksrt'),
+            'templates/pages/page-cart.php' => __('AKSRT - 购物车', 'aksrt'),
+            'templates/pages/page-messages.php' => __('AKSRT - 消息中心', 'aksrt'),
+            'templates/pages/page-product.php' => __('AKSRT - 商品详情', 'aksrt'),
+            'templates/pages/page-product-edit.php' => __('AKSRT - 商品编辑', 'aksrt'),
+            'templates/pages/page-forums.php' => __('AKSRT - 论坛', 'aksrt'),
+            'templates/forum/forum-compose.php' => __('AKSRT - 发帖', 'aksrt'),
+        ];
+    }
+
+    /**
+     * Register selectable page templates in wp-admin.
+     */
+    public function register_page_templates(array $templates): array {
+        foreach ($this->page_template_map() as $template_file => $label) {
+            $templates[$template_file] = $label;
+        }
+
+        return $templates;
+    }
+
+    /**
+     * Resolve theme page templates through the shared page-template router.
+     */
+    public function load_page_template(string $template): string {
+        global $post;
+
+        if (!$post) {
+            return $template;
+        }
+
+        $page_template_meta = get_post_meta($post->ID, '_wp_page_template', true);
+        $resolved_template = function_exists('aksrt_resolve_page_template_file')
+            ? aksrt_resolve_page_template_file(
+                is_string($page_template_meta) ? $page_template_meta : '',
+                (string) $post->post_name
+            )
+            : '';
+
+        if ($resolved_template !== '' && function_exists('aksrt_locate_template_file')) {
+            $resolved_path = aksrt_locate_template_file($resolved_template);
+            if ($resolved_path) {
+                return $resolved_path;
+            }
+        }
+
+        return $template;
+    }
+
+    public function template_hierarchy(array $templates): array {
+        return $templates;
+    }
+
+    /**
+     * Load dedicated product taxonomy templates.
+     */
+    public function load_taxonomy_template(string $template): string {
+        if (is_tax('aksrt_product_cat')) {
+            $cat_template = AKSRT_DIR . '/templates/shop/product-cat.php';
+            if (file_exists($cat_template)) {
+                return $cat_template;
+            }
+        }
+
+        if (is_tax('aksrt_product_tag')) {
+            $tag_template = AKSRT_DIR . '/templates/shop/product-tag.php';
+            if (file_exists($tag_template)) {
+                return $tag_template;
+            }
+        }
+
+        return $template;
+    }
+
+    public function render_archive_shortcode(array $attrs = [], string $content = ''): string {
+        $template = AKSRT_DIR . '/templates/shortcodes/archive.php';
+        if (!file_exists($template)) {
+            return '';
+        }
+        ob_start();
+        include $template;
+        return (string) ob_get_clean();
+    }
+
+    public function render_profile_shortcode(array $attrs = [], string $content = ''): string {
+        $template = AKSRT_DIR . '/templates/shortcodes/profile.php';
+        if (!file_exists($template)) {
+            return '';
+        }
+        ob_start();
+        include $template;
+        return (string) ob_get_clean();
+    }
+}