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/Ticket/TicketRestAdmin.php

@@ -362,7 +362,7 @@ final class TicketRestAdmin {
         $quote_id = absint($request->get_param('quote_reply_id'));
         if ($quote_id > 0) {
             $quoted = $repo->find_reply($quote_id);
-            if ($quoted === null || (int) $quoted['ticket_id'] !== $id) {
+            if ($quoted === null || (int) $quoted['ticket_id'] !== $id || $quoted['author_type'] === 'system') {
                 $quote_id = 0;
             }
         }