fix: 前端统一解析后端 detail 报错，杜绝 [object Object]

各处 catch 里直接 `toast(err?.response?.data?.detail ?? "xx失败")` 有坑：
请求体校验失败(422)时 detail 是数组，React 会把每个对象渲染成 [object Object]。

- utils/errorMessage.ts（新增）: extractErrorMessage 统一解析三种形态 ——
  字符串 / FastAPI 校验错误数组 / 对象；数组取 msg 并剥掉 Pydantic 的
  "Value error, " 前缀、带上字段名、同字段去重后用「；」拼接；解析不出内容
  则回落到调用方给的兜底文案。行为与移动端 extractErrorDetail 对齐
- 19 处调用点全部替换：AdminTasksPage(4) / AdminProductsPage(5) /
  TaskTreeViewer(4) / AdminPrintConfigPage(2) / ScanPage / CreateProductDialog /
  ImageUploader / authApi
- TaskRejectPayload.images 与 taskApi.rejectTask 的注释同步为「选填，支持空数组」
- 新增 components/ui/ImageUploader.tsx（驳回弹窗选图上传组件），
  RejectModal 同步放开无图拦截：去掉 images 非空校验、提交按钮不再因
  无图禁用、标签由必填星号改为「（选填，最多 9 张）」，并移除因此失效的
  error 状态
- AdminTasksPage.tsx: 支持大屏下钻的 ?search / ?status / ?stage 预设参数，
  新增「售后流转中」状态 Tab（按 lifecycle_phase 判定）与全局重置；
  ?stage 只在跳入时生效一次，用户手动改条件即解除锁定
- 杂项清理: TaskFlowView 移除透传的 assigneeNames、TaskListCard/MyTasksPage
  移除未使用导入、QrScanner 关闭 verbose 日志

frontend/src/components/TaskTree/TaskFlowView.tsx

@@ -3,7 +3,7 @@
  */
 import { memo, useMemo, useState, useEffect } from "react";
 import { Image } from "antd";
-import { FileText, Package, User, X } from "lucide-react";
+import { Package, User, X } from "lucide-react";
 import type { TaskResponse } from "../../types/api";
 import { TASK_STATUS } from "../../types/api";
 import { getStatusConfig } from "../../constants/task";
@@ -87,14 +87,13 @@ const SIZE_MAP = {
 // 极简卡片
 // ============================================================
 const SlimCard = memo(function SlimCard({
-  task, assigneeName, active, legacy, onAction, currentUser, onViewRecords, rootMainId, size = "sm", assigneeNames,
+  task, assigneeName, active, legacy, onAction, currentUser, onViewRecords, rootMainId, size = "sm",
 }: {
   task: TaskResponse; assigneeName?: string; active: boolean; legacy?: boolean;
   onAction: (t: ModalTarget) => void; currentUser?: { username?: string; role?: string } | null;
   onViewRecords?: (t: TaskResponse) => void;
   rootMainId?: string;
   size?: "sm" | "lg";
-  assigneeNames?: Record<string, string>;
 }) {
   const cfg = getStatusConfig(task.status);
   const sz = SIZE_MAP[size];
@@ -232,7 +231,7 @@ export const TaskFlowView = memo(function TaskFlowView({ tasks, onAction, curren
     const arrow = side === 'left'
       ? (<div className="flex items-center"><ArrowLeft color={isLegacy ? "#fdba74" : "#9ca3af"} big={big} /><div className={`${big ? "w-10 border-t-[3px]" : "w-6 border-t-2"} ${isLegacy ? "border-dashed border-orange-300" : "border-solid border-gray-400"}`} /></div>)
       : (<div className="flex items-center"><div className={`${big ? "w-10 border-t-[3px]" : "w-6 border-t-2"} ${isLegacy ? "border-dashed border-orange-300" : "border-solid border-gray-400"}`} /><ArrowRight color={isLegacy ? "#fdba74" : "#9ca3af"} big={big} /></div>);
-    const card = <SlimCard task={node} active={active(node.status)} legacy={isLegacy} assigneeName={assigneeNames?.[node.assignee_id || ""]} onAction={onAction} currentUser={currentUser} onViewRecords={setRecordsTask} rootMainId={rootMainId} size={size} assigneeNames={assigneeNames} />;
+    const card = <SlimCard task={node} active={active(node.status)} legacy={isLegacy} assigneeName={assigneeNames?.[node.assignee_id || ""]} onAction={onAction} currentUser={currentUser} onViewRecords={setRecordsTask} rootMainId={rootMainId} size={size} />;
     const kidsContainer = kids.length > 0 ? (
       <div className={`flex flex-col gap-2 ${side === 'left' ? 'items-end' : 'items-start'}`}>
         {kids.map(k => renderBranch(k, side, isLegacy, rootMainId))}
@@ -299,7 +298,7 @@ export const TaskFlowView = memo(function TaskFlowView({ tasks, onAction, curren
                 {/* 中央 */}
                 <div className="shrink-0 z-10 relative">
                   <SlimCard task={mainTask} active={active(mainTask.status)}
-                    assigneeName={assigneeNames?.[mainTask.assignee_id || ""]} onAction={onAction} currentUser={currentUser} onViewRecords={setRecordsTask} size={size} assigneeNames={assigneeNames} />
+                    assigneeName={assigneeNames?.[mainTask.assignee_id || ""]} onAction={onAction} currentUser={currentUser} onViewRecords={setRecordsTask} size={size} />
                   {active(mainTask.status) && (
                     <div className={`absolute -top-1 -left-1 rounded-full bg-green-400 border-2 border-white ${size === "lg" ? "h-4 w-4" : "h-3 w-3"}`} />
                   )}