feat: 物品规则接单金额可填0并限制零元发布，客服增加发单指派权限

- 物品规则接单金额允许填 0（按数量计价不受影响）
- 接单金额为 0 的工单禁止发布：前端发布按钮置灰 + 后端 409 拦截
- 客服（support）获得发布工单与指派打手权限

apps/backend/src/routes/admin/worker-platform.ts

@@ -344,7 +344,7 @@ router.put(
 
 router.post(
   '/worker-platform/orders/:workOrderId/assign',
-  requireAdminRoles(['admin', 'operator']),
+  requireAdminRoles(['admin', 'operator', 'support']),
   createJsonHandler(
     (req) => assignAdminWorkOrderToWorker(String(req.params.workOrderId || ''), req.body || {}),
     {
@@ -379,7 +379,7 @@ router.delete(
 
 router.post(
   '/worker-platform/orders/:workOrderId/publish',
-  requireAdminRoles(['admin', 'operator']),
+  requireAdminRoles(['admin', 'operator', 'support']),
   createJsonHandler((req) => publishAdminWorkOrder(String(req.params.workOrderId || '')), {
     successMessage: '订单已发布到抢单大厅',
     errorMessage: '发布接单订单失败',