feat(cost-center): 渠道映射改为诊断优先，新增未归一队列

- 顶部统计卡：标准商品 / 映射 / 未归一订单项 / 未归一 SKU 组
- 新增「未归一」队列：按来源+店铺+平台SKU+履约方式聚合，行内建映射并预填
- 目录表从 7 列精简到 4 列，匹配方式移入展开明细
- 回填订单项后自动把已归一的 product_mapping_missing 异常收口
- 新增 /cost-center/mappings/diagnostics 与 /mappings/unmapped，按履约方式拆分聚合避免全表扫描

apps/backend/src/routes/admin/cost-center.ts

@@ -27,8 +27,10 @@ import {
   createAdminProduct,
   deleteAdminChannelMapping,
   deleteAdminProduct,
+  getAdminChannelMappingDiagnostics,
   listAdminChannelMappings,
   listAdminProducts,
+  listAdminUnmappedMappingGroups,
   updateAdminChannelMapping,
   updateAdminProduct,
 } from '../../services/cost-center/product-catalog-service.js'
@@ -273,6 +275,26 @@ router.get(
   }),
 )
 
+router.get(
+  '/cost-center/mappings/diagnostics',
+  requireAdminPermission('finance.view'),
+  createJsonHandler((req) => getAdminChannelMappingDiagnostics(req.query as JsonObject), {
+    successMessage: 'ok',
+    errorMessage: '读取渠道映射诊断失败',
+    scope: '[admin/cost-center/mappings/diagnostics]',
+  }),
+)
+
+router.get(
+  '/cost-center/mappings/unmapped',
+  requireAdminPermission('finance.view'),
+  createJsonHandler((req) => listAdminUnmappedMappingGroups(req.query as JsonObject), {
+    successMessage: 'ok',
+    errorMessage: '读取未归一队列失败',
+    scope: '[admin/cost-center/mappings/unmapped]',
+  }),
+)
+
 router.post(
   '/cost-center/mappings',
   requireAdminPermission('finance.config'),