重构：前端架构优化 - 消灭巨石文件，统一代码规范

Phase 1 - 消灭巨石页面：
- 拆分 AdminKuaishouCloudFulfillmentView (1,224行→kuaishou-cloud/子目录)
- 拆分 AdminFulfillmentBindingsView (989行→bindings/子目录)
- 拆分 AdminTaskDetailView (1,007行→9个子组件+2个composable)
- 合并去重 useClaimPage + useAdminManualRedeemPage (1,554行→共享模块+差异化薄层)
- 拆分 services/admin/platform-config.ts (477行→8个领域子模块)

Phase 2 - 架构收口：
- 拆分 types/admin.ts (925行→13个子文件+platform-config/子目录)
- 统一 API code 检查（http.ts拦截器统一处理业务错误）
- 修改 apiPost 签名消除 as unknown as 类型断言（6处）
- 新增 BusinessError 类型便于错误分类处理

所有改动通过 vue-tsc --noEmit 零错误和 vite build 验证

apps/frontend/src/views/admin/fulfillment/AdminFulfillmentConfigHubView.vue

@@ -2,8 +2,8 @@
 import { computed } from 'vue'
 import { useRoute, useRouter } from 'vue-router'
 
-import AdminFulfillmentBindingsView from './AdminFulfillmentBindingsView.vue'
-import AdminKuaishouCloudFulfillmentView from './AdminKuaishouCloudFulfillmentView.vue'
+import AdminFulfillmentBindingsView from './bindings/AdminFulfillmentBindingsView.vue'
+import AdminKuaishouCloudFulfillmentView from './kuaishou-cloud/AdminKuaishouCloudFulfillmentView.vue'
 
 type FulfillmentTabKey = 'legacy' | 'kuaishou-cloud'