fix(ui): stabilize settings apply flow and mobile/admin UX

packages/ui/src/api/mePreferences.ts

@@ -1,3 +1,4 @@
+import { ApiError } from "./errors";
 import { createApiClient } from "./client";
 import type { components } from "./schema";
 
@@ -7,7 +8,14 @@ export type UserPreferencesPatch = components["schemas"]["UserPreferencesPatch"]
 export const createMePreferencesApi = (client: ReturnType<typeof createApiClient>) => {
   return {
     getPreferences: async (): Promise<User> => {
-      return client.request<User>({ path: "/me/preferences" });
+      try {
+        return await client.request<User>({ path: "/me/preferences" });
+      } catch (error) {
+        if (error instanceof ApiError && error.status === 404) {
+          return client.request<User>({ path: "/me" });
+        }
+        throw error;
+      }
     },
     setPreferences: async (payload: UserPreferencesPatch): Promise<User> => {
       return client.request<User>({

packages/ui/src/app/AdminAppearancePage.tsx

@@ -1,7 +1,7 @@
 import React, { useCallback, useMemo, useState } from "react";
 import { Button, ErrorState, LoadingSkeleton, PageHeader, Toolbar } from "@nimbus/ui-kit";
 import type { I18nKey } from "../i18n/t";
-import { t } from "../i18n/t";
+import { setLocale, t } from "../i18n/t";
 import { getAuthenticatedApiClient } from "./authenticatedApiClient";
 import { createMePreferencesApi } from "../api/mePreferences";
 import type { components } from "../api/schema";
@@ -63,6 +63,7 @@ export default function AdminAppearancePage() {
     try {
       const me = await api.getPreferences();
 
+      setLocale(me.locale);
       const profile: AppearanceConfig = {
         locale: me.locale,
         theme: themeRef.current,
@@ -83,9 +84,13 @@ export default function AdminAppearancePage() {
 
     try {
       await api.setPreferences({ locale: draft.locale });
+      setLocale(draft.locale);
       toggleTheme(draft.theme);
       setCurrent(draft);
       setMessageKey("admin.appearance.saved");
+      if (typeof window !== "undefined") {
+        window.setTimeout(() => window.location.reload(), 120);
+      }
     } catch {
       setErrorKey("admin.appearance.saveError");
     } finally {

packages/ui/src/app/AdminShell.css

@@ -75,3 +75,40 @@
   color: var(--nd-color-accent-default);
   font-weight: 600;
 }
+
+@media (max-width: 900px) {
+  .admin-shell {
+    flex-direction: column;
+  }
+
+  .admin-shell__sidebar {
+    width: 100%;
+    border-right: none;
+    border-bottom: 1px solid var(--nd-color-border-default);
+    padding: 10px;
+    gap: 8px;
+  }
+
+  .admin-shell__title,
+  .admin-shell__subtitle {
+    font-size: 11px;
+  }
+
+  .admin-shell__nav {
+    flex-direction: row;
+    flex-wrap: nowrap;
+    gap: 6px;
+    overflow-x: auto;
+    padding-bottom: 2px;
+  }
+
+  .admin-shell__link {
+    margin-bottom: 0;
+    white-space: nowrap;
+    flex: 0 0 auto;
+  }
+
+  .admin-shell__content {
+    padding: 12px;
+  }
+}

packages/ui/src/app/AppShell.css

@@ -53,6 +53,9 @@
   color: var(--nd-color-text-primary);
   margin-right: var(--nd-space-4);
   white-space: nowrap;
+  text-decoration: none;
+  display: inline-flex;
+  align-items: center;
 }
 
 .app-shell__search {

packages/ui/src/app/AppShell.tsx

@@ -105,7 +105,9 @@ export function AppShell() {
         <header className="app-shell__topbar">
           <div className="app-shell__topbar-left">
 
-            <div className="app-shell__brand">{t("app.brand")}</div>
+            <NavLink to="/files" className="app-shell__brand" aria-label={t("nav.files")}>
+              {t("app.brand")}
+            </NavLink>
             <input
               aria-label={t("field.search")}
               placeholder={t("field.search")}

packages/ui/src/i18n/t.ts

@@ -3,14 +3,37 @@ import en from "./locales/en-US.json";
 
 export type Locale = "ko-KR" | "en-US";
 
+const LOCALE_KEY = "ui.appearance.locale";
+
 const dictionaries = {
   "ko-KR": ko,
   "en-US": en,
 } as const;
 
 export type I18nKey = keyof typeof dictionaries["ko-KR"];
 
-export const t = (key: I18nKey, locale: Locale = "ko-KR"): string => {
-  const dict = dictionaries[locale] ?? dictionaries["ko-KR"];
+let currentLocale: Locale = "ko-KR";
+
+if (typeof window !== "undefined") {
+  const saved = window.localStorage.getItem(LOCALE_KEY);
+  if (saved === "ko-KR" || saved === "en-US") {
+    currentLocale = saved;
+  }
+}
+
+export function getLocale(): Locale {
+  return currentLocale;
+}
+
+export function setLocale(locale: Locale) {
+  currentLocale = locale;
+  if (typeof window !== "undefined") {
+    window.localStorage.setItem(LOCALE_KEY, locale);
+  }
+}
+
+export const t = (key: I18nKey, locale?: Locale): string => {
+  const effectiveLocale = locale ?? currentLocale;
+  const dict = dictionaries[effectiveLocale] ?? dictionaries["ko-KR"];
   return dict[key] ?? key;
 };