fix(report): carry the admin note into the reporter result email

update_status() fired aksrt_report_status_changed without the note and
the mail listener hard-coded note => '', so the reply-to-reporter
comment written in the process form never reached the email. Pass the
sanitized note as a 4th action arg, render it via the existing {note}
placeholder, and map the raw status key to its Chinese label in the
email body. Contract test extended accordingly.

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

@@ -137,6 +137,11 @@ test('admin report notification links to the real page', () => {
   assert.match(mailNotifications, /users\.php\?page=aksrt_user_ban'/)
   assert.ok(!mailNotifications.includes('page=aksrt_reports&'), 'dead admin page link')
   assert.ok(!mailNotifications.includes('tab=reports'), 'merged ticket page has no reports tab')
+  // 处理说明必须随 aksrt_report_status_changed 传入邮件载荷（此前硬编码空串，
+  // 举报人收到的“说明：”永远为空）。
+  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 :/)
 })
 
 test('native ban page mirrors the reference theme layout', () => {