feat(cost-center): 第三方卡券渠道完整接入成本模型

- 商品来源筛选补 tpv: 前缀，卡券商品列表不再为空
- 成本模型新增 third_party_voucher_cost，覆盖预览/成本项/概览作用域
- 前后端成本模型枚举与下拉同步

apps/frontend/src/pages/admin/cost-center/shared.ts

@@ -78,6 +78,7 @@ export type CostVersionFormValues = {
 export const COST_MODEL_OPTIONS = [
   { value: 'affiliate_purchase', label: '上游采购成本' },
   { value: 'work_order_reward', label: '接单平台打手报酬' },
+  { value: 'third_party_voucher_cost', label: '第三方卡券采购成本' },
   { value: 'manual_actual', label: '人工客服实际支出' },
   { value: 'platform_fee', label: '平台服务费' },
   { value: 'payment_fee', label: '支付通道费' },

apps/frontend/src/types/admin/cost-center.ts

@@ -18,6 +18,7 @@ export type ProductSource = 'affiliate_dash' | 'work_order' | 'third_party_vouch
 export type CostModel =
   | 'affiliate_purchase'
   | 'work_order_reward'
+  | 'third_party_voucher_cost'
   | 'manual_actual'
   | 'platform_fee'
   | 'payment_fee'