收紧后端 TypeScript：统一 Json 类型与 TaskContext 契约

关闭 allowJs；集中 JsonObject 定义并替换分散 any 别名；parseTaskContext 返回 TaskContext；任务详情 API 标注 AdminTaskDetailView；测试减少 as any。

apps/backend/src/services/admin/admin-task-read-helpers.ts

@@ -1,6 +1,7 @@
 import { getTaskById } from '../../repositories/task-repo.js'
 import { createHttpError } from '../../utils/http.js'
 import { safeParseJson } from './admin-query-utils.js'
+import { asJsonObject, type  JsonObject, JsonRecord  } from '../../types/json.js'
 import {
   TASK_STATUS,
   isTaskFulfillmentCompletedStatus,
@@ -22,8 +23,6 @@ import type {
 } from '../../types/repository/rows.js'
 import type { AdminViewerContext } from './admin-read-shared-helpers.js'
 
-type JsonRecord = Record<string, any>
-
 type TaskFulfillmentState = {
   resourceStatus: string
   customerStatus: string
@@ -263,7 +262,7 @@ function isTaskFulfillmentCompleted(task: TaskRow | null | undefined): boolean {
 }
 
 function normalizeRecord(value: unknown): JsonRecord {
-  return value && typeof value === 'object' && !Array.isArray(value) ? value : {}
+  return asJsonObject(value)
 }
 
 function getTaskRetryCount(task: TaskRow | null | undefined): number {