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/used-car/list.module.css

@@ -0,0 +1,39 @@
+.usedCarListPage {
+  min-height: 100vh;
+  background: #f4f6f8;
+  padding-bottom: 20px;
+}
+
+/* 搜索和筛选栏 */
+.searchFilterBar {
+  position: sticky;
+  top: 0;
+  z-index: 100;
+  background: #fff;
+  padding: 12px 16px;
+  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.06);
+  display: flex;
+  gap: 12px;
+  align-items: center;
+}
+
+/* 使用 :global 包裹第三方组件类名 */
+.searchFilterBar :global(.adm-search-bar) {
+  flex: 1;
+  min-width: 0;
+}
+
+/* 列表容器 - 减少左右间距 */
+.listContainer {
+  padding: 12px 8px;
+}
+
+/* 覆盖 InfiniteScroll 默认样式 - 只影响当前页面 */
+.listContainer :global(.adm-infinite-scroll) {
+  padding: 0;
+  display: block;
+}
+
+.listContainer :global(.adm-infinite-scroll-content) {
+  display: block;
+}