拆分接单平台超长文件，按域组织代码

- worker-platform-service.ts (2733行) 拆为 worker-service/admin-service/mappers + index 聚合
- worker-platform-repo.ts (2456行) 拆为 repositories/worker-platform/ 目录（types/shared/worker-repo/work-order-repo）
- AdminWorkerPlatformPage.tsx (2784行) 拆为主页面 + panels/ 目录（7 个面板文件）
- 引用方统一改指向 index 聚合，行为不变

apps/backend/src/routes/worker/session.ts

@@ -4,7 +4,7 @@ import {
   requireActiveWorkerSession,
   verifyWorkerSessionToken,
   type WorkerSession,
-} from '../../services/worker-platform/worker-platform-service.js'
+} from '../../services/worker-platform/index.js'
 import { createHttpError, sendRouteError } from '../../utils/http.js'
 
 export async function requireWorkerSession(req: Request, res: Response, next: NextFunction): Promise<void> {