feat(report): route report notices into the in-site message system

Ban appeals already sent site messages to admins and to the appellant,
but reports only produced emails: the submit path never notified admins
in-site and the status change path never notified the reporter. Send a
'report' site message to administrators on submit (deep link to the
ticket list) and to the reporter on status change (status label plus
the admin note), matching the appeal flow's direct-send pattern.
Contract test extended accordingly.

tests/widget-system/report-ban-contract.test.cjs

@@ -142,6 +142,12 @@ test('admin report notification links to the real page', () => {
   assert.match(reportCenter, /do_action\('aksrt_report_status_changed', \$report_id[\s\S]*?new_status, \$note_clean\)/)
   assert.match(mailNotifications, /function report_status_changed\(int \$report_id, int \$reporter_id, string \$status, string \$note = ''\)/)
   assert.match(mailNotifications, /'note'\s*=>\s*\$note !== '' \? \$note :/)
+  // 举报通知必须入站内消息系统：提交→管理员（直达工单列表）、
+  // 处理结果→举报人（与结果邮件同一时机、同一说明）。
+  assert.match(reportCenter, /notify_admins_new_report\(/)
+  assert.match(reportCenter, /notify_reporter_status_changed\(/)
+  assert.match(reportCenter, /Message::get_instance\(\)->send\(/)
+  assert.match(reportCenter, /users\.php\?page=aksrt_user_ban&tab=tickets/)
 })
 
 test('native ban page mirrors the reference theme layout', () => {