公开页补齐自引用 Canonical 与按类型的结构化数据，图片补上说明文字。

后台设置和内容编辑改成可导航布局；部署用访客 origin 生成 Canonical，避免落到容器地址。

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/components/admin/index.ts

@@ -2,6 +2,13 @@ export { default as AdminPageHeader } from "./AdminPageHeader";
 export { default as AdminSection } from "./AdminSection";
 export { default as AdminSwitch } from "./AdminSwitch";
 export { default as AdminSettingRow } from "./AdminSettingRow";
+export {
+  AdminSettingsPage,
+  AdminSettingsWork,
+  AdminSettingsGroup,
+  AdminSettingsRow,
+  AdminSettingsActions,
+} from "./AdminSettingsLayout";
 export { default as AdminSegmented } from "./AdminSegmented";
 export type { AdminSegmentOption } from "./AdminSegmented";
 export { default as AdminSearchField } from "./AdminSearchField";