接单工单支持置顶，抢单大厅优先展示

- 新增 work_orders.pinned_at 字段与迁移
- 管理端对已发布（待抢单）订单提供置顶/取消置顶操作，置顶订单带标记
- 抢单大厅按置顶时间优先排序，打手端卡片展示置顶标签

apps/frontend/src/pages/admin/panels/WorkOrdersPanel.tsx

@@ -4,6 +4,7 @@ import {
   EditOutlined,
   FormOutlined,
   PlusOutlined,
+  PushpinOutlined,
   ReloadOutlined,
   SearchOutlined,
   SendOutlined,
@@ -63,6 +64,7 @@ import {
   fetchAdminWorkerUsers,
   fetchAdminWorkOrders,
   markAdminWorkOrderProblem,
+  pinAdminWorkOrder,
   publishAdminWorkOrder,
   reviewAdminWorkerFinanceRequest,
   resolveAdminProblemWorkOrder,
@@ -693,11 +695,16 @@ export default function WorkOrdersPanel() {
     },
     {
       title: '状态',
-      width: 130,
+      width: 150,
       render: (_, row) => (
-        <Tag color={resolveStatusColor(row.status)}>
-          {formatStatus(row.status)}
-        </Tag>
+        <Space wrap size={4}>
+          <Tag color={resolveStatusColor(row.status)}>
+            {formatStatus(row.status)}
+          </Tag>
+          {row.status === 'open' && row.pinnedAt ? (
+            <Tag color="gold" icon={<PushpinOutlined />}>置顶</Tag>
+          ) : null}
+        </Space>
       ),
     },
     {
@@ -795,6 +802,20 @@ export default function WorkOrdersPanel() {
               发布
             </Button>
           ) : null}
+          {row.status === 'open' ? (
+            <Button
+              icon={<PushpinOutlined />}
+              title={row.pinnedAt ? '取消置顶' : '置顶后抢单大厅优先展示'}
+              onClick={() =>
+                runAction(
+                  () => pinAdminWorkOrder(row.workOrderId, !row.pinnedAt),
+                  row.pinnedAt ? '已取消置顶' : '已置顶，抢单大厅优先展示',
+                )
+              }
+            >
+              {row.pinnedAt ? '取消置顶' : '置顶'}
+            </Button>
+          ) : null}
           {row.status === 'open' ? (
             <Button
               danger