接入 ESLint 并清理未使用代码

- 前后端接入 ESLint 10 扁平配置（typescript-eslint 类型感知检查 + react-hooks/react-refresh），新增 lint / lint:check / lint:fix 脚本并纳入 check 链路
- 清理全部 no-unused-vars 与 no-useless-assignment 警告，修复 floating promises、正则转义等问题
- 删除确认无引用的死代码（markKuaishouCloudBindUrlRefreshFailed、未使用 helper 等）

apps/backend/src/services/admin/admin-read-service.ts

@@ -5,7 +5,7 @@ import { listOrderItemsByOrderId } from '../../repositories/order-item-repo.js'
 import { getOrderById, listOrders } from '../../repositories/order-repo.js'
 import { getTaskById, listTasks, listTasksByOrderId } from '../../repositories/task-repo.js'
 import { listTaskEventsByTaskId } from '../../repositories/task-event-repo.js'
-import type { JsonObject, JsonRecord } from '../../types/json.js'
+import type { JsonRecord } from '../../types/json.js'
 import {
   listKuaishouIndustryVouchersByOid,
   listKuaishouIndustryVouchersByTaskId,
@@ -474,7 +474,7 @@ function buildCloudSourceLabelMap() {
 
 export async function getAdminTaskScreenshotPath(
   taskId: AdminEntityIdInput,
-  session: AdminViewerSessionInput | null = null,
+  _session: AdminViewerSessionInput | null = null,
 ): Promise<string> {
   const task = await getRequiredTask(taskId)