feat: 客服封存订单功能（号主失联场景）

新增客服「封存订单」动作，用于号主失联、无法联系的场景：单事务内
完成关闭订单、全量原路退款、永久封存关联商品、解散发布群、双方通知
与审计日志。

- 新增 listing 终态 sealed（封存），区别于可恢复的 offline
- listingLockedForOwnerMutation 锁定 sealed，号主无法再编辑/提审/上架
- 解散群聊按 listing_id 查发布群（listing_group）置 archived，
  阻断所有成员发言并留系统消息
- 新增 order.AdminSeal 及 /admin/orders/:id/seal 路由
- 前端：卖家页 PC/移动端 sealed 视为终态禁用操作，客服后台新增
  「封存订单」按钮与二次确认

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend/src/features/admin/views/AdminOrderDetailView.vue

@@ -10,6 +10,7 @@ import {
   adminRefundOrder,
   adminRefundStatus,
   adminResetHandoff,
+  adminSealOrder,
   fetchAdminHandoffRecords,
   fetchAdminOrder,
   type HandoffRecord,
@@ -40,7 +41,7 @@ const submitting = ref(false)
 const order = ref<Order | null>(null)
 const handoffRecords = ref<HandoffRecord[]>([])
 const paymentRecords = ref<AdminPayment[]>([])
-const actionType = ref<'close' | 'abnormal' | 'reset' | ''>('')
+const actionType = ref<'close' | 'seal' | 'abnormal' | 'reset' | ''>('')
 const reason = ref('')
 const refundStatus = ref<RefundStatus | null>(null)
 
@@ -89,10 +90,13 @@ const resetActionLabel = computed(() => {
 const canResetHandoff = computed(() => resetAction.value?.enabled === true)
 const actionTitle = computed(() => {
   if (actionType.value === 'close') return '客服关闭订单'
+  if (actionType.value === 'seal') return '封存订单'
   if (actionType.value === 'reset') return `${resetActionLabel.value}（恢复到对应待办）`
   return '标记订单异常'
 })
 const closeActionTip = '关闭订单并归档商品/账号；已支付订单会按租金+实付押金全量原路退款。'
+const sealActionTip =
+  '封存订单：终止订单并全量原路退款，自动解散关联群聊，关联商品永久封存，号主无法再次编辑或上架。适用于号主失联、无法联系的场景。'
 const refundActionTip = '仅发起后台人工全量原路退款，不关闭订单或调整商品/账号状态。'
 const refundButtonDisabled = computed(() => refundStatus.value?.refund_status === 'refunded')
 const orderTotalCent = computed(
@@ -201,7 +205,7 @@ async function loadRefundStatus() {
   }
 }
 
-function openAction(type: 'close' | 'abnormal' | 'reset') {
+function openAction(type: 'close' | 'seal' | 'abnormal' | 'reset') {
   actionType.value = type
   reason.value = ''
 }
@@ -224,6 +228,24 @@ async function confirmCloseAction() {
   openAction('close')
 }
 
+async function confirmSealAction() {
+  if (!order.value || !canOperate.value) return
+  try {
+    await ElMessageBox.confirm(
+      '封存会终止订单并全量原路退款，自动解散关联群聊，关联商品将被永久封存，号主无法再次编辑或上架。适用于号主失联场景。确认继续？',
+      '确认封存订单',
+      {
+        confirmButtonText: '继续封存',
+        cancelButtonText: '取消',
+        type: 'warning',
+      }
+    )
+  } catch {
+    return
+  }
+  openAction('seal')
+}
+
 async function submitAction() {
   if (!order.value || !actionType.value) return
   submitting.value = true
@@ -231,6 +253,9 @@ async function submitAction() {
     if (actionType.value === 'close') {
       await adminCloseOrder(order.value.id, reason.value)
       ElMessage.success('订单已关闭')
+    } else if (actionType.value === 'seal') {
+      await adminSealOrder(order.value.id, reason.value)
+      ElMessage.success('订单已封存，群聊已解散')
     } else if (actionType.value === 'reset') {
       await adminResetHandoff(order.value.id, reason.value)
       ElMessage.success(`${resetActionLabel.value}成功`)
@@ -467,6 +492,13 @@ function paymentPaidAt(record: AdminPayment) {
             >
           </span>
         </el-tooltip>
+        <el-tooltip :content="sealActionTip" placement="top">
+          <span>
+            <el-button type="danger" plain :disabled="!canOperate" @click="confirmSealAction"
+              >封存订单</el-button
+            >
+          </span>
+        </el-tooltip>
         <el-tooltip :content="refundActionTip" placement="top">
           <span>
             <el-button