继续收紧 TypeScript：ClaimIdentity 契约与 flow 出口类型

- 新增 types/claim-identity，统一 ClaimIdentity / Payload / AdminSummary
- 导出 KuaishouCloudFlow、KuaishouFeifeiFlow 作为 normalize 出口
- 生产路径 JsonObject 统一从 types/json 导入，去掉 rebind as any
- 前后端 claimIdentity 类型字段对齐

apps/backend/src/services/notification/domain-notifications.ts

@@ -1,10 +1,10 @@
+import type { JsonObject } from '../../types/json.js'
 import { logWarn } from '../../utils/logger.js'
 import { sendInternalNotification } from './notification-service.js'
 
 const DEFAULT_COOLDOWN_MS = 10 * 60 * 1000
 const notificationCooldownMap = new Map<string, number>()
 
-type JsonObject = Record<string, unknown>
 type InternalNotificationPayload = {
   title: string
   body?: string