feat(frontend): align single related/prevnext/maxheight with Zibll

Honor prevnext/authordesc/yiyan settings, multi-tax related queries with
orderby (incl. views), per-post maxheight override, and only expand content
when maxheight is enabled.

inc/classes/admin/schema/class-aksrt-admin-schema-post-list.php

@@ -103,6 +103,8 @@ class AKSRT_Admin_Schema_Post_List {
                                 ['label' => '随机', 'value' => 'rand'],
                                 ['label' => '相关度', 'value' => 'relevance'],
                                 ['label' => '时间', 'value' => 'date'],
+                                ['label' => '浏览量', 'value' => 'views'],
+                                ['label' => '更新时间', 'value' => 'modified'],
                             ]],
                             ['key' => 'post_related_title', 'label' => '推荐标题', 'type' => 'input', 'default' => '相关推荐'],
                         ]],

inc/classes/class-aksrt-settings.php

@@ -903,7 +903,7 @@ class AKSRT_Settings {
             $related_type = 'category';
         }
         $related_orderby = sanitize_key((string) ($settings['post_related_orderby'] ?? 'rand'));
-        if (!in_array($related_orderby, ['rand', 'relevance', 'date'], true)) {
+        if (!in_array($related_orderby, ['rand', 'relevance', 'date', 'views', 'modified'], true)) {
             $related_orderby = 'rand';
         }
 

inc/classes/settings/class-aksrt-settings-post-display.php

@@ -221,7 +221,7 @@ class AKSRT_Settings_Post_Display {
             'related_enabled'          => !isset($settings['post_related_enabled']) || !empty($settings['post_related_enabled']),
             'related_count'            => max(1, min(20, (int) ($settings['post_related_count'] ?? 6))),
             'related_type'             => in_array(sanitize_key((string) ($settings['post_related_type'] ?? 'category')), ['category', 'tag', 'random'], true) ? sanitize_key((string) ($settings['post_related_type'] ?? 'category')) : 'category',
-            'related_orderby'          => in_array(sanitize_key((string) ($settings['post_related_orderby'] ?? 'rand')), ['rand', 'relevance', 'date'], true) ? sanitize_key((string) ($settings['post_related_orderby'] ?? 'rand')) : 'rand',
+            'related_orderby'          => in_array(sanitize_key((string) ($settings['post_related_orderby'] ?? 'rand')), ['rand', 'relevance', 'date', 'views', 'modified'], true) ? sanitize_key((string) ($settings['post_related_orderby'] ?? 'rand')) : 'rand',
             'related_title'            => sanitize_text_field((string) ($settings['post_related_title'] ?? '相关推荐')),
             'like_enabled'             => !isset($settings['post_like_enabled']) || !empty($settings['post_like_enabled']),
             'favorite_enabled'         => !isset($settings['post_favorite_enabled']) || !empty($settings['post_favorite_enabled']),