feat(links): move friend links to native WordPress links with review flow

- enable the native Links manager and drop the custom friend-link option/REST path
- add per-page link settings for the friends template
- render link categories from get_bookmarks() with search and page-content options
- add a validated public link submission endpoint with logo upload, captcha, rate limiting and duplicate checks
- create pending links for review and notify administrators by email and in-app message
- add native Links admin pending count, columns and edit notes
- cover the new submission and cleanup contracts

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

src/Core/ScriptsPart1b.php

@@ -536,20 +536,39 @@ trait ScriptsPart1b {
             );
         }
 
-        // 友情链接页：路由专属 CSS
+        // 友情链接页：原生链接列表 + 申请表单
         if (is_page_template('templates/pages/page-friends.php')) {
-            wp_enqueue_style(
-                'jio-route-friends',
-                $base_uri . '/assets/css/routes/friends.css',
-                ['jio-public'],
-                file_exists(get_template_directory() . '/assets/css/routes/friends.css')
-                    ? (string) filemtime(get_template_directory() . '/assets/css/routes/friends.css')
-                    : $version
-            );
+            $links_css = get_template_directory() . '/assets/css/routes/links.css';
+            if (file_exists($links_css)) {
+                wp_enqueue_style(
+                    'jio-route-links',
+                    $base_uri . '/assets/css/routes/links.css',
+                    ['jio-public'],
+                    (string) filemtime($links_css)
+                );
+            }
+            $links_js = get_template_directory() . '/assets/js/links-submit.js';
+            if (file_exists($links_js)) {
+                wp_enqueue_script(
+                    'jio-links-submit',
+                    $base_uri . '/assets/js/links-submit.js',
+                    ['loader_js'],
+                    (string) filemtime($links_js),
+                    true
+                );
+                wp_localize_script('jio-links-submit', 'jioLinksSubmit', [
+                    'ajaxUrl' => admin_url('admin-ajax.php'),
+                    'i18n'    => [
+                        'submitting' => __('正在提交…', 'jio'),
+                        'success'    => __('提交成功', 'jio'),
+                        'error'      => __('提交失败，请重试', 'jio'),
+                        'captcha'    => __('请完成人机验证', 'jio'),
+                    ],
+                ]);
+            }
         }
 
-        // 网址导航页（legacy links.php）
-        // 文章导航页（legacy postsnavs.php）
+        // 文章导航页（postsnavs.php）
         if (is_page_template('templates/pages/page-posts-navs.php')) {
             $page_navs_js = get_template_directory() . '/assets/js/page-navs.js';
             if (file_exists($page_navs_js)) {