fix(worker): 整单指派拼单订单无法验收

- 前端：拼单订单整单指派给本人时放行验收
- 后端：整单指派清掉 sharing_enabled；已有有效份额则拒绝

apps/backend/src/services/worker-platform/admin-work-order-assignment-service.ts

@@ -4,6 +4,7 @@ import {
   countWorkerActiveOrders,
   createWorkOrderEvent,
   getWorkerUserById,
+  listWorkOrderShares,
 } from '../../repositories/worker-platform/index.js'
 import type { JsonObject } from '../../types/json.js'
 import { createHttpError } from '../../utils/http.js'
@@ -64,6 +65,18 @@ export async function assignAdminWorkOrderToWorker(
     })
   }
 
+  // 已有拼单份额的订单不能再按整单指派；放在核销电子凭证之前，
+  // 避免“凭证已核销但指派失败”的副作用。
+  const activeShares = (await listWorkOrderShares(workOrder.id)).filter(
+    (share) => share.status !== 'cancelled',
+  )
+  if (activeShares.length > 0) {
+    throw createHttpError('该订单已有拼单份额，不能按整单指派；请使用拼单管理', {
+      statusCode: 409,
+      errorCode: 'work_order_has_shares',
+    })
+  }
+
   const voucherConsume = await consumeIndustryVouchersBeforeWorkOrderAssign(workOrder)
   if (!voucherConsume.ok) {
     const failedAt = nowIso()
@@ -112,6 +125,15 @@ export async function assignAdminWorkOrderToWorker(
       { statusCode: 409, errorCode: 'worker_deposit_insufficient' },
     )
   }
+  if (failureReason === 'work_order_has_shares') {
+    throw createHttpError(
+      resolveAssignFailureMessage(
+        voucherConsume.voucherCount,
+        '该订单已有拼单份额，不能按整单指派；请使用拼单管理',
+      ),
+      { statusCode: 409, errorCode: 'work_order_has_shares' },
+    )
+  }
   if (!updated) {
     throw createHttpError(
       resolveAssignFailureMessage(voucherConsume.voucherCount, '指派失败，订单状态可能已变化'),