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/backend/src/services/worker-platform/admin-service.ts

@@ -1083,6 +1083,32 @@ export async function unpublishAdminWorkOrder(workOrderId: number | string) {
   return { order: mapWorkOrderAdmin(updated || workOrder) }
 }
 
+export async function pinAdminWorkOrder(workOrderId: number | string, payload: JsonObject = {}) {
+  const workOrder = await getRequiredWorkOrder(workOrderId)
+  const pinned = payload.pinned === true
+  if (pinned && workOrder.status !== WORK_ORDER_STATUS.OPEN) {
+    throw createHttpError('只有待抢单订单可以置顶', {
+      statusCode: 409,
+      errorCode: 'work_order_pin_status_invalid',
+    })
+  }
+  const now = nowIso()
+  const updated = await updateWorkOrder(workOrder.id, {
+    pinned_at: pinned ? now : null,
+    updated_at: now,
+  })
+  await createWorkOrderEvent({
+    workOrderId: workOrder.id,
+    actorType: 'admin',
+    actorId: '',
+    eventType: pinned ? 'pinned' : 'unpinned',
+    fromStatus: workOrder.status,
+    toStatus: workOrder.status,
+    now,
+  })
+  return { order: mapWorkOrderAdmin(updated || workOrder) }
+}
+
 export async function markAdminWorkOrderProblem(
   workOrderId: number | string,
   payload: JsonObject = {},

apps/backend/src/services/worker-platform/mappers.ts

@@ -404,6 +404,7 @@ export function mapWorkOrderAdmin(workOrder: WorkOrderRow) {
         }
       : null,
     publishedAt: workOrder.published_at,
+    pinnedAt: workOrder.pinned_at,
     assignedAt: workOrder.assigned_at,
     submittedAt: workOrder.submitted_at,
     acceptedAt: workOrder.accepted_at,

apps/backend/src/services/worker-platform/worker-service.ts

@@ -824,6 +824,7 @@ export async function listWorkerHallOrders(query: JsonObject = {}, session: Work
     keyword: String(query.keyword || '').trim(),
     categoryId: categoryId || 0,
     visibleAfterIso,
+    pinnedFirst: true,
   })
   const categories = (await listWorkCategories()).map(mapWorkCategory)
   const myShares = await listWorkerSharesByWorker(worker.id)