feat(settings): wire Playback + Scrobbling panels to the backend

Adds src/api/endpoints/settings.ts (getSettings/updateSettings,
getScrobbling/updateScrobbling) plus AppSettings/ScrobblingConfig types
and a Settings cache tag. Replaces the "coming soon" scaffolds:

- Playback: stream-quality preference (SegmentedControl), server-synced.
- Scrobbling: enable + provider (Last.fm/ListenBrainz) + username +
  write-only session key, with a linked/not-linked badge and save states.

Built with modern-sk (Window/SegmentedControl/TextField/Button/Callout/
Badge) + the shared Loading/Error states; en + ru strings added. Server
state flows through RTK Query hooks only (no fetch in components).

Also drops a pre-existing unused TextField import in LibraryPage that was
failing `tsc --noEmit`.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/api/endpoints/settings.ts

@@ -0,0 +1,90 @@
+import { api } from '../index';
+import type {
+  AppSettings,
+  ScrobbleProvider,
+  ScrobblingConfig,
+  StreamQuality,
+  ThemePref,
+} from '../types';
+
+// Wire shapes (snake_case) from the backend, mapped to the app's camelCase types.
+interface RawSettings {
+  theme: ThemePref;
+  stream_quality: StreamQuality;
+}
+interface RawScrobbling {
+  enabled: boolean;
+  provider: ScrobbleProvider | null;
+  username: string | null;
+  configured: boolean;
+}
+
+const toSettings = (r: RawSettings): AppSettings => ({
+  theme: r.theme,
+  streamQuality: r.stream_quality,
+});
+const toScrobbling = (r: RawScrobbling): ScrobblingConfig => ({
+  enabled: r.enabled,
+  provider: r.provider,
+  username: r.username,
+  configured: r.configured,
+});
+
+export const settingsApi = api.injectEndpoints({
+  endpoints: (build) => ({
+    getSettings: build.query<AppSettings, void>({
+      query: () => '/settings',
+      transformResponse: (raw: RawSettings) => toSettings(raw),
+      providesTags: ['Settings'],
+    }),
+    updateSettings: build.mutation<
+      AppSettings,
+      { theme?: ThemePref; streamQuality?: StreamQuality }
+    >({
+      query: ({ theme, streamQuality }) => ({
+        url: '/settings',
+        method: 'PATCH',
+        body: { theme, stream_quality: streamQuality },
+      }),
+      transformResponse: (raw: RawSettings) => toSettings(raw),
+      invalidatesTags: ['Settings'],
+    }),
+    getScrobbling: build.query<ScrobblingConfig, void>({
+      query: () => '/settings/scrobbling',
+      transformResponse: (raw: RawScrobbling) => toScrobbling(raw),
+      providesTags: ['Settings'],
+    }),
+    updateScrobbling: build.mutation<
+      ScrobblingConfig,
+      {
+        enabled: boolean;
+        provider: ScrobbleProvider | null;
+        username: string | null;
+        // Write-only: send only when the user typed a new key; omit to keep the
+        // stored one (the server never returns it).
+        sessionKey?: string;
+      }
+    >({
+      query: ({ enabled, provider, username, sessionKey }) => ({
+        url: '/settings/scrobbling',
+        method: 'PUT',
+        body: {
+          enabled,
+          provider,
+          username,
+          session_key: sessionKey,
+        },
+      }),
+      transformResponse: (raw: RawScrobbling) => toScrobbling(raw),
+      invalidatesTags: ['Settings'],
+    }),
+  }),
+  overrideExisting: false,
+});
+
+export const {
+  useGetSettingsQuery,
+  useUpdateSettingsMutation,
+  useGetScrobblingQuery,
+  useUpdateScrobblingMutation,
+} = settingsApi;

src/api/index.ts

@@ -23,6 +23,7 @@ export const api = createApi({
     'Like',
     'User',
     'Storage',
+    'Settings',
   ],
   // Tier 2 offline: seed the cache from the persisted snapshot dispatched at
   // startup (see `store/rtkqPersist.ts`). Returning the saved queries/mutations

src/api/types.ts

@@ -258,3 +258,24 @@ export interface MetadataEdit {
   genre?: string;
   trackNumber?: number;
 }
+
+// -- user settings (`/settings`) ---------------------------------------------
+export type ThemePref = 'system' | 'light' | 'dark';
+export type StreamQuality = 'original' | 'high' | 'medium' | 'low';
+
+/** General per-user preferences from `GET /settings`. */
+export interface AppSettings {
+  theme: ThemePref;
+  streamQuality: StreamQuality;
+}
+
+export type ScrobbleProvider = 'lastfm' | 'listenbrainz';
+
+/** Scrobbling config from `GET /settings/scrobbling`. The session key is
+ * write-only server-side, so it never appears here — only `configured`. */
+export interface ScrobblingConfig {
+  enabled: boolean;
+  provider: ScrobbleProvider | null;
+  username: string | null;
+  configured: boolean;
+}

src/features/library/LibraryPage.tsx

@@ -7,7 +7,6 @@ import {
   TabsContent,
   ScrollArea,
   Card,
-  TextField,
   Callout,
   SearchField,
 } from '@olly/modern-sk';

src/features/settings/panels.tsx

@@ -1,7 +1,27 @@
-import type { ReactNode } from 'react';
+import { useEffect, useState, type ReactNode } from 'react';
 import { useTranslation } from 'react-i18next';
-import { Window, SegmentedControl, useTheme } from '@olly/modern-sk';
+import {
+  Window,
+  SegmentedControl,
+  TextField,
+  Button,
+  Callout,
+  Badge,
+  useTheme,
+} from '@olly/modern-sk';
 import { SUPPORTED_LANGUAGES, setLanguage } from '../../i18n';
+import { LoadingSkeleton } from '../../components/common/LoadingSkeleton';
+import { ErrorState } from '../../components/common/ErrorState';
+import {
+  useGetSettingsQuery,
+  useUpdateSettingsMutation,
+  useGetScrobblingQuery,
+  useUpdateScrobblingMutation,
+} from '../../api/endpoints/settings';
+import type {
+  ScrobbleProvider,
+  StreamQuality,
+} from '../../api/types';
 
 /** Labelled settings row: caption on the left, control on the right. */
 function SettingRow({
@@ -27,6 +47,14 @@ function SettingRow({
   );
 }
 
+const labelStyle: React.CSSProperties = {
+  display: 'block',
+  fontSize: '0.8125rem',
+  fontWeight: 500,
+  marginBottom: '0.375rem',
+  color: 'var(--color-text-2)',
+};
+
 /** `/settings/profile` — profile + app language + theme (all wired). */
 export function ProfileSettings() {
   const { t, i18n } = useTranslation();
@@ -66,26 +94,224 @@ export function ProfileSettings() {
   );
 }
 
-/** `/settings/playback` — default stream quality / playback behaviour. Scaffold. */
+const STREAM_QUALITIES: StreamQuality[] = ['original', 'high', 'medium', 'low'];
+
+/** `/settings/playback` — default stream quality (server-synced). */
 export function PlaybackSettings() {
   const { t } = useTranslation();
+  const { data, isLoading, isError, refetch } = useGetSettingsQuery();
+  const [updateSettings, { isLoading: isSaving }] = useUpdateSettingsMutation();
+
   return (
     <Window title={t('settings.tabs.playback')}>
-      <p style={{ color: 'var(--color-text-2)', margin: 0 }}>
-        {t('common.comingSoon')}
+      {isLoading && <LoadingSkeleton rows={1} height={40} />}
+      {isError && (
+        <ErrorState message={t('common.error')} onRetry={() => refetch()} />
+      )}
+      {data && (
+        <div
+          style={{
+            padding: '0.75rem 0',
+            display: 'flex',
+            flexDirection: 'column',
+            gap: '1rem',
+          }}
+        >
+          <SettingRow label={t('settings.playback.streamQuality')}>
+            <SegmentedControl
+              value={data.streamQuality}
+              onValueChange={(v) =>
+                void updateSettings({ streamQuality: v as StreamQuality })
+              }
+              items={STREAM_QUALITIES.map((q) => ({
+                value: q,
+                label: t(`settings.playback.quality.${q}`),
+              }))}
+            />
+          </SettingRow>
+          <p
+            style={{
+              margin: 0,
+              fontSize: '0.8rem',
+              color: 'var(--color-text-3)',
+            }}
+          >
+            {isSaving
+              ? t('settings.common.saving')
+              : t('settings.playback.streamQualityHint')}
           </p>
+        </div>
+      )}
     </Window>
   );
 }
 
-/** `/settings/scrobbling` — last.fm / ListenBrainz linking. Scaffold. */
+const PROVIDERS: ScrobbleProvider[] = ['lastfm', 'listenbrainz'];
+
+/** `/settings/scrobbling` — Last.fm / ListenBrainz linking (server-synced). */
 export function ScrobblingSettings() {
   const { t } = useTranslation();
+  const { data, isLoading, isError, refetch } = useGetScrobblingQuery();
+  const [updateScrobbling, { isLoading: isSaving }] =
+    useUpdateScrobblingMutation();
+
+  const [enabled, setEnabled] = useState(false);
+  const [provider, setProvider] = useState<ScrobbleProvider>('lastfm');
+  const [username, setUsername] = useState('');
+  const [sessionKey, setSessionKey] = useState('');
+  const [status, setStatus] = useState<'idle' | 'saved' | 'error'>('idle');
+
+  // Seed the form from the server once it loads (and on refetch).
+  useEffect(() => {
+    if (data) {
+      setEnabled(data.enabled);
+      setProvider(data.provider ?? 'lastfm');
+      setUsername(data.username ?? '');
+    }
+  }, [data]);
+
+  const handleSave = async () => {
+    setStatus('idle');
+    try {
+      await updateScrobbling({
+        enabled,
+        provider: enabled ? provider : null,
+        username: username.trim() || null,
+        sessionKey: sessionKey || undefined,
+      }).unwrap();
+      setSessionKey(''); // the key is write-only — don't keep it around
+      setStatus('saved');
+    } catch {
+      setStatus('error');
+    }
+  };
+
   return (
     <Window title={t('settings.tabs.scrobbling')}>
-      <p style={{ color: 'var(--color-text-2)', margin: 0 }}>
-        {t('common.comingSoon')}
+      {isLoading && <LoadingSkeleton rows={3} height={40} />}
+      {isError && (
+        <ErrorState message={t('common.error')} onRetry={() => refetch()} />
+      )}
+      {data && (
+        <div
+          style={{
+            padding: '0.75rem 0',
+            display: 'flex',
+            flexDirection: 'column',
+            gap: '1.25rem',
+          }}
+        >
+          <div
+            style={{
+              display: 'flex',
+              alignItems: 'center',
+              justifyContent: 'space-between',
+              gap: '1rem',
+            }}
+          >
+            <p
+              style={{
+                margin: 0,
+                fontSize: '0.875rem',
+                color: 'var(--color-text-2)',
+              }}
+            >
+              {t('settings.scrobbling.description')}
             </p>
+            <Badge variant={data.configured ? 'lime' : 'neutral'}>
+              {data.configured
+                ? t('settings.scrobbling.configured')
+                : t('settings.scrobbling.notConfigured')}
+            </Badge>
+          </div>
+
+          <SettingRow label={t('settings.scrobbling.enabled')}>
+            <SegmentedControl
+              value={enabled ? 'on' : 'off'}
+              onValueChange={(v) => setEnabled(v === 'on')}
+              items={[
+                { value: 'on', label: t('settings.scrobbling.on') },
+                { value: 'off', label: t('settings.scrobbling.off') },
+              ]}
+            />
+          </SettingRow>
+
+          {enabled && (
+            <>
+              <SettingRow label={t('settings.scrobbling.provider')}>
+                <SegmentedControl
+                  value={provider}
+                  onValueChange={(v) => setProvider(v as ScrobbleProvider)}
+                  items={PROVIDERS.map((p) => ({
+                    value: p,
+                    label: t(`settings.scrobbling.${p}`),
+                  }))}
+                />
+              </SettingRow>
+
+              <div>
+                <label style={labelStyle}>
+                  {t('settings.scrobbling.username')}
+                </label>
+                <TextField
+                  value={username}
+                  onChange={(e) => setUsername(e.target.value)}
+                  placeholder={t('settings.scrobbling.usernamePlaceholder')}
+                  autoComplete="off"
+                />
+              </div>
+
+              <div>
+                <label style={labelStyle}>
+                  {t('settings.scrobbling.sessionKey')}
+                </label>
+                <TextField
+                  type="password"
+                  value={sessionKey}
+                  onChange={(e) => setSessionKey(e.target.value)}
+                  placeholder={
+                    data.configured
+                      ? t('settings.scrobbling.sessionKeyKeep')
+                      : t('settings.scrobbling.sessionKeyPlaceholder')
+                  }
+                  autoComplete="off"
+                />
+                <span
+                  style={{
+                    display: 'block',
+                    fontSize: '0.75rem',
+                    color: 'var(--color-text-3)',
+                    marginTop: '0.375rem',
+                  }}
+                >
+                  {t('settings.scrobbling.sessionKeyHint')}
+                </span>
+              </div>
+            </>
+          )}
+
+          {status === 'saved' && (
+            <Callout variant="success">
+              {t('settings.scrobbling.saved')}
+            </Callout>
+          )}
+          {status === 'error' && (
+            <Callout variant="danger">{t('settings.scrobbling.error')}</Callout>
+          )}
+
+          <div>
+            <Button
+              variant="primary"
+              disabled={isSaving}
+              onClick={() => void handleSave()}
+            >
+              {isSaving
+                ? t('settings.common.saving')
+                : t('settings.common.save')}
+            </Button>
+          </div>
+        </div>
+      )}
     </Window>
   );
 }

src/i18n/locales/en.ts

@@ -357,6 +357,41 @@ const en = {
       scrobbling: 'Scrobbling',
       instance: 'Instance',
     },
+    common: {
+      save: 'Save',
+      saving: 'Saving…',
+    },
+    playback: {
+      streamQuality: 'Streaming quality',
+      streamQualityHint:
+        'Audio quality when streaming from the server. "Original" streams the file as-is.',
+      quality: {
+        original: 'Original',
+        high: 'High',
+        medium: 'Medium',
+        low: 'Low',
+      },
+    },
+    scrobbling: {
+      description: 'Send your listens to Last.fm or ListenBrainz.',
+      configured: 'Linked',
+      notConfigured: 'Not linked',
+      enabled: 'Scrobbling',
+      on: 'On',
+      off: 'Off',
+      provider: 'Service',
+      lastfm: 'Last.fm',
+      listenbrainz: 'ListenBrainz',
+      username: 'Username',
+      usernamePlaceholder: 'your account name',
+      sessionKey: 'Session key / token',
+      sessionKeyPlaceholder: 'paste your token',
+      sessionKeyKeep: 'leave blank to keep the current token',
+      sessionKeyHint:
+        'Stored encrypted on the server and never shown again.',
+      saved: 'Scrobbling settings saved.',
+      error: 'Could not save. Please try again.',
+    },
   },
   admin: {
     userDetail: 'User',

src/i18n/locales/ru.ts

@@ -358,6 +358,41 @@ const ru: Translations = {
       scrobbling: 'Скробблинг',
       instance: 'Сервер',
     },
+    common: {
+      save: 'Сохранить',
+      saving: 'Сохранение…',
+    },
+    playback: {
+      streamQuality: 'Качество потока',
+      streamQualityHint:
+        'Качество звука при стриминге с сервера. «Оригинал» отдаёт файл как есть.',
+      quality: {
+        original: 'Оригинал',
+        high: 'Высокое',
+        medium: 'Среднее',
+        low: 'Низкое',
+      },
+    },
+    scrobbling: {
+      description: 'Отправляйте свои прослушивания в Last.fm или ListenBrainz.',
+      configured: 'Подключено',
+      notConfigured: 'Не подключено',
+      enabled: 'Скробблинг',
+      on: 'Вкл',
+      off: 'Выкл',
+      provider: 'Сервис',
+      lastfm: 'Last.fm',
+      listenbrainz: 'ListenBrainz',
+      username: 'Имя пользователя',
+      usernamePlaceholder: 'ваш логин',
+      sessionKey: 'Ключ сессии / токен',
+      sessionKeyPlaceholder: 'вставьте токен',
+      sessionKeyKeep: 'оставьте пустым, чтобы сохранить текущий токен',
+      sessionKeyHint:
+        'Хранится на сервере в зашифрованном виде и больше не показывается.',
+      saved: 'Настройки скробблинга сохранены.',
+      error: 'Не удалось сохранить. Попробуйте ещё раз.',
+    },
   },
   admin: {
     userDetail: 'Пользователь',

src/index.tsx

@@ -21,6 +21,7 @@ import './api/endpoints/search';
 import './api/endpoints/likes';
 import './api/endpoints/storage';
 import './api/endpoints/admin';
+import './api/endpoints/settings';
 import './api/endpoints/upload';
 
 // Tier 3 offline: register the audio-caching service worker (no-op if the