feat: add used-car module and fix API response handling

- Add used-car pages: list, detail, create, edit, mine
- Add CarCard and PriceModal components
- Fix API response interceptor to accept both code 200 and 0
- Fix detail page: was incorrectly using edit page template
- Fix edit page: remove res.code check after API call
- Add image URL processing (localhost → localhost:8787)
- Add i18n translations for used-car module in 5 languages

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/pages/dashboard/index.tsx

@@ -35,12 +35,15 @@ const quickActions: QuickAction[] = [
   { id: '1', icon: '✈️', label: '出差申请', path: '/business-trip/apply', color: '#1677ff', description: '提交出差申请' },
   { id: '2', icon: '📝', label: '采购申请', path: '/purchase/apply', color: '#52c41a', description: '物品采购审批', disabled: true },
   { id: '3', icon: '📦', label: '备货录入', path: '/stock/entry', color: '#faad14', description: '库存备货录入', disabled: true },
+  { id: '4', icon: '🚗', label: '发布车辆', path: '/used-car/create', color: '#722ed1', description: '发布二手车' },
+  { id: '5', icon: '📋', label: '我的发布', path: '/used-car/my-list', color: '#722ed1', description: '我发布的车辆' },
 ]
 
 const allApps: QuickAction[] = [
   { id: '1', icon: '✍️', label: '审批', path: '/approval', color: '#52c41a', description: '待办事项审批' },
   { id: '2', icon: '📊', label: '数据统计', path: '/reports', color: '#1890ff', description: '业务数据统计', disabled: true },
   { id: '3', icon: '⚙️', label: '系统设置', path: '/settings', color: '#8c8c8c', description: '系统偏好设置' },
+  { id: '4', icon: '🚗', label: '二手车', path: '/used-car', color: '#722ed1', description: '二手车管理' },
 ]
 
 export default function Dashboard() {