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/scheduler/scheduler-service.ts

@@ -1,13 +1,12 @@
 import { logError, logInfo, logWarn } from '../../utils/logger.js'
 import { createHttpError } from '../../utils/http.js'
+import type { JsonObject } from '../../types/json.js'
 import {
   getCloudtentaclesHealthJob,
   getScheduledJobsConfig,
 } from './config-service.js'
 import { runCloudtentaclesHealthJob } from './cloudtentacles-health-job.js'
 
-type JsonObject = Record<string, any>
-
 const timers = new Map<string, NodeJS.Timeout>()
 const jobStates = new Map<string, JsonObject>()