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/config-service.ts

@@ -1,4 +1,5 @@
 import path from 'node:path'
+import type { JsonObject } from '../../types/json.js'
 
 import { APP_CONFIG_KEYS } from '../../config/app-config-keys.js'
 import { PROJECT_ROOT } from '../../config/runtime.js'
@@ -10,8 +11,6 @@ import {
 const SCHEDULED_JOBS_FILE_PATH = path.join(PROJECT_ROOT, 'data', 'scheduled-jobs.json')
 const CLOUDTENTACLES_HEALTH_JOB_ID = 'cloudtentacles-health'
 
-type JsonObject = Record<string, any>
-
 export function getScheduledJobsFilePath() {
   return SCHEDULED_JOBS_FILE_PATH
 }