feat(ticket): record urges in thread, show urge count in admin, mail admins

- aksrt_ticket gains urge_count / last_urge_time (schema 3.1.0)
- cooldown moves from transient to an atomic conditional UPDATE
- urge inserts a system reply rendered as a centered notice (not quotable)
- admin list badge + info card row for urge count / last time
- new ticket_urge_admin mail event via aksrt_ticket_urged

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/Admin/Native/UsersMenusTicketsDetail.php

@@ -49,6 +49,12 @@ trait UsersMenusTicketsDetail {
         } else {
             $html .= '<ol class="aksrt-ticket-detail__replies">';
             foreach ($replies as $reply) {
+                if ((string) $reply['author_type'] === 'system') {
+                    // 系统记录（如催单）：居中提示行，无头像 / 引用 / 附件。
+                    $html .= '<li class="aksrt-ticket-detail__system"><span>' . esc_html((string) $reply['content'])
+                        . '</span><time>' . esc_html((string) $reply['created_at']) . '</time></li>';
+                    continue;
+                }
                 $is_admin = (string) $reply['author_type'] === 'admin';
                 $html .= '<li class="aksrt-ticket-detail__reply is-' . ($is_admin ? 'admin' : 'user') . '">';
                 $html .= $this->ticket_message_head(
@@ -159,6 +165,17 @@ trait UsersMenusTicketsDetail {
         }
         $rows[__('提交时间', 'aksrt')] = esc_html((string) $ticket['post_time']);
         $rows[__('最后回复', 'aksrt')] = esc_html((string) $ticket['last_reply_time'] !== '' ? (string) $ticket['last_reply_time'] : '—');
+        if ((int) $ticket['urge_count'] > 0) {
+            $rows[__('催单', 'aksrt')] = '<span class="aksrt-ticket-urge">' . esc_html(sprintf(
+                /* translators: %d urge count */
+                __('%d 次', 'aksrt'),
+                (int) $ticket['urge_count']
+            )) . '</span> <span class="aksrt-tickets-admin__muted">' . esc_html(sprintf(
+                /* translators: %s last urge time */
+                __('最近 %s', 'aksrt'),
+                (string) $ticket['last_urge_time']
+            )) . '</span>';
+        }
 
         $html = '<section class="aksrt-ticket-detail__card"><dl class="aksrt-ticket-detail__info">';
         foreach ($rows as $label => $value) {