feat(forum): guest cash purchase for topic and plate follow

- Reuse pay_no_logged_in / pay_cookie_day; generalized guest cookie helpers
- Topic + plate cash: guest preview/purchase (no balance), order.user_id=0, cookie unlock
- View gates: can_view_topic pay + plate follow accept signed guest cookies
- Templates: guest buy/follow CTAs; poll endpoint allows plate_follow guest orders

templates/forum/forum-plate.php

@@ -106,6 +106,20 @@ $max_pages      = (int) ($view['pagination']['max_pages'] ?? 1);
             </div>
 
             <div class="aksrt-forum-board__actions">
+                <?php
+                $follow_pay_on = $forum && method_exists($forum, 'is_plate_follow_pay_enabled')
+                    ? $forum->is_plate_follow_pay_enabled($plate_id)
+                    : ((int) get_post_meta($plate_id, '_aksrt_follow_pay', true) === 1);
+                $follow_pay_modo = sanitize_key((string) (get_post_meta($plate_id, '_aksrt_follow_pay_modo', true) ?: 'money'));
+                $allow_guest_plate = $current_user_id <= 0
+                    && $follow_pay_on
+                    && $follow_pay_modo === 'money'
+                    && function_exists('aksrt_allow_guest_forum_pay')
+                    && aksrt_allow_guest_forum_pay(get_post($plate_id));
+                $guest_followed = $current_user_id <= 0
+                    && function_exists('aksrt_guest_has_plate_follow_access')
+                    && aksrt_guest_has_plate_follow_access($plate_id);
+                ?>
                 <?php if ($current_user_id > 0) : ?>
                     <button type="button"
                         class="aksrt-forum-board__follow-btn js-aksrt-follow-plate"
@@ -114,6 +128,21 @@ $max_pages      = (int) ($view['pagination']['max_pages'] ?? 1);
                         <i class="fas fa-heart"></i>
                         <?php echo $is_followed ? esc_html__('已关注', 'aksrt') : esc_html__('关注', 'aksrt'); ?>
                     </button>
+                <?php elseif ($guest_followed) : ?>
+                    <button type="button" class="aksrt-forum-board__follow-btn is-followed" disabled>
+                        <i class="fas fa-heart"></i>
+                        <?php esc_html_e('已关注', 'aksrt'); ?>
+                    </button>
+                <?php elseif ($allow_guest_plate) : ?>
+                    <button type="button"
+                        class="aksrt-forum-board__follow-btn"
+                        data-aksrt-pay-plate-follow="<?php echo esc_attr((string) $plate_id); ?>">
+                        <i class="fas fa-heart"></i>
+                        <?php esc_html_e('付费关注', 'aksrt'); ?>
+                    </button>
+                    <p class="description" style="margin-top:6px;font-size:12px;">
+                        <?php esc_html_e('未登录关注通过 Cookie 生效；建议登录后关注以便保存订单。', 'aksrt'); ?>
+                    </p>
                 <?php endif; ?>
 
                 <?php if (!empty($permissions['can_compose'])) : ?>