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/utils/task-json.ts

@@ -1,26 +1,34 @@
-export type JsonRecord = Record<string, any>
+import type { JsonObject, JsonRecord } from '../types/json.js'
+import { asJsonObject, isPlainObject } from '../types/json.js'
+import type { TaskContext } from '../types/task-context.js'
 
-export function parseJsonObject(value: unknown): JsonRecord {
+export type { JsonRecord, JsonObject }
+
+export function parseJsonObject(value: unknown): JsonObject {
   if (!value) {
     return {}
   }
 
-  if (typeof value === 'object' && !Array.isArray(value)) {
-    return value as JsonRecord
+  if (isPlainObject(value)) {
+    return value
   }
 
   try {
-    const parsed = JSON.parse(String(value || '{}'))
-    return parsed && typeof parsed === 'object' && !Array.isArray(parsed) ? parsed : {}
+    const parsed = JSON.parse(String(value || '{}')) as unknown
+    return asJsonObject(parsed)
   } catch {
     return {}
   }
 }
 
-export function parseTaskContext(task: { context_json?: unknown } | null | undefined): JsonRecord {
-  return parseJsonObject(task?.context_json)
+export function parseTaskContext(
+  task: { context_json?: unknown } | null | undefined,
+): TaskContext {
+  return parseJsonObject(task?.context_json) as TaskContext
 }
 
-export function parseTaskState(task: { state_json?: unknown } | null | undefined): JsonRecord {
+export function parseTaskState(
+  task: { state_json?: unknown } | null | undefined,
+): JsonObject {
   return parseJsonObject(task?.state_json)
 }