feat(admin): wire instance health panel + settings instance (A9/A10)

AdminInstance shows backing-service health (db/redis/ml), read-only source
status (env-configured), and a library reindex with graceful handling when no
indexable source exists. InstanceSettings shows the active instance and offers
switch/sign-out to /connect. Adds getServices/getSources/reindex endpoints.

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

src/api/endpoints/admin.ts

@@ -1,6 +1,11 @@
 import { api } from '../index';
 import { toUser, type RawUser } from '../mappers';
-import type { User } from '../types';
+import type { User, ServicesStatus, SourceInfo } from '../types';
+
+interface ReindexJob {
+  source: string;
+  jobId: string;
+}
 
 /**
  * Admin user management. The backend models authorization as `is_superuser` /
@@ -59,6 +64,20 @@ export const adminApi = api.injectEndpoints({
         body: { new_password: newPassword },
       }),
     }),
+    // -- instance (§A9) -------------------------------------------------------
+    getServices: build.query<ServicesStatus, void>({
+      query: () => '/admin/services',
+    }),
+    getSources: build.query<SourceInfo[], void>({
+      query: () => '/admin/sources',
+    }),
+    reindex: build.mutation<ReindexJob[], void>({
+      query: () => ({ url: '/admin/reindex', method: 'POST' }),
+      transformResponse: (raw: { jobs: { source: string; job_id: string }[] }) =>
+        raw.jobs.map((j) => ({ source: j.source, jobId: j.job_id })),
+      // A fresh scan changes the catalogue once the worker runs.
+      invalidatesTags: ['Track', 'Album', 'Artist', 'Storage'],
+    }),
   }),
   overrideExisting: false,
 });
@@ -70,4 +89,7 @@ export const {
   useUpdateUserMutation,
   useDeleteUserMutation,
   useResetPasswordMutation,
+  useGetServicesQuery,
+  useGetSourcesQuery,
+  useReindexMutation,
 } = adminApi;

src/api/types.ts

@@ -140,6 +140,16 @@ export interface UploadResponse {
   already_exists: boolean;
 }
 
+/** One backing-dependency probe result (GET /admin/services). `skipped` = the
+ * dependency is optional and not configured (e.g. ML with no ML_SERVICE_URL). */
+export type ServiceStatus = 'ok' | 'down' | 'skipped';
+
+export interface ServicesStatus {
+  database: ServiceStatus;
+  redis: ServiceStatus;
+  ml: ServiceStatus;
+}
+
 export interface StorageFormatBreakdown {
   fileFormat: string;
   trackCount: number;

src/features/admin/panels.tsx

@@ -29,8 +29,11 @@ import {
   useUpdateUserMutation,
   useDeleteUserMutation,
   useResetPasswordMutation,
+  useGetServicesQuery,
+  useGetSourcesQuery,
+  useReindexMutation,
 } from '../../api/endpoints/admin';
-import type { User } from '../../api/types';
+import type { User, ServiceStatus } from '../../api/types';
 
 function StubPanel({ title }: { title: string }) {
   const { t } = useTranslation();
@@ -475,8 +478,174 @@ export function AdminSources() {
   return <StubPanel title={t('admin.tabs.sources')} />;
 }
 
-/** `/admin/instance` — service health, ML_SERVICE_URL, reindex. Scaffold. */
+const SERVICE_VARIANT: Record<ServiceStatus, 'lime' | 'ember' | 'neutral'> = {
+  ok: 'lime',
+  down: 'ember',
+  skipped: 'neutral',
+};
+
+/** `/admin/instance` — backing-service health, source status, library reindex. */
 export function AdminInstance() {
   const { t } = useTranslation();
-  return <StubPanel title={t('admin.tabs.instance')} />;
+  const {
+    data: servicesData,
+    isLoading: servicesLoading,
+    isError: servicesError,
+    refetch: refetchServices,
+  } = useGetServicesQuery();
+  const {
+    data: sourcesData,
+    isLoading: sourcesLoading,
+    isError: sourcesError,
+    refetch: refetchSources,
+  } = useGetSourcesQuery();
+  const [reindex, { isLoading: isReindexing }] = useReindexMutation();
+  const [reindexMsg, setReindexMsg] = useState<
+    { kind: 'success' | 'danger'; text: string } | null
+  >(null);
+
+  const handleReindex = async () => {
+    setReindexMsg(null);
+    try {
+      const jobs = await reindex().unwrap();
+      setReindexMsg({
+        kind: 'success',
+        text: t('admin.instance.reindex.enqueued', { count: jobs.length }),
+      });
+    } catch {
+      // 400 when no indexable source is configured (see admin.py::trigger_reindex).
+      setReindexMsg({
+        kind: 'danger',
+        text: t('admin.instance.reindex.noSource'),
+      });
+    }
+  };
+
+  return (
+    <Window title={t('admin.tabs.instance')}>
+      <div style={{ display: 'flex', flexDirection: 'column', gap: '1.5rem' }}>
+        {/* ── Services ─────────────────────────────────────────────── */}
+        <section>
+          <h3 style={{ margin: '0 0 0.5rem', fontSize: '0.95rem' }}>
+            {t('admin.instance.services.title')}
+          </h3>
+          {servicesLoading && <LoadingSkeleton rows={3} height={40} />}
+          {servicesError && <ErrorState onRetry={refetchServices} />}
+          {servicesData && (
+            <div
+              style={{ display: 'flex', flexDirection: 'column', gap: '0.5rem' }}
+            >
+              {(['database', 'redis', 'ml'] as const).map((key) => {
+                const status = servicesData[key];
+                return (
+                  <Card
+                    key={key}
+                    style={{
+                      padding: '0.625rem 1rem',
+                      display: 'flex',
+                      alignItems: 'center',
+                      gap: '1rem',
+                    }}
+                  >
+                    <span style={{ flex: 1 }}>
+                      {t(`admin.instance.services.${key}`)}
+                    </span>
+                    <Badge variant={SERVICE_VARIANT[status]} dot>
+                      {t(`admin.instance.status.${status}`)}
+                    </Badge>
+                  </Card>
+                );
+              })}
+            </div>
+          )}
+        </section>
+
+        {/* ── Sources (read-only; configured via env) ──────────────── */}
+        <section>
+          <h3 style={{ margin: '0 0 0.25rem', fontSize: '0.95rem' }}>
+            {t('admin.instance.sources.title')}
+          </h3>
+          <p
+            style={{
+              margin: '0 0 0.5rem',
+              fontSize: '0.8125rem',
+              color: 'var(--color-text-3)',
+            }}
+          >
+            {t('admin.instance.sources.envNote')}
+          </p>
+          {sourcesLoading && <LoadingSkeleton rows={2} height={40} />}
+          {sourcesError && <ErrorState onRetry={refetchSources} />}
+          {sourcesData && sourcesData.length === 0 && (
+            <EmptyState icon="⊘" title={t('admin.instance.sources.empty')} />
+          )}
+          {sourcesData && sourcesData.length > 0 && (
+            <div
+              style={{ display: 'flex', flexDirection: 'column', gap: '0.5rem' }}
+            >
+              {sourcesData.map((s) => (
+                <Card
+                  key={s.name}
+                  style={{
+                    padding: '0.625rem 1rem',
+                    display: 'flex',
+                    alignItems: 'center',
+                    gap: '1rem',
+                  }}
+                >
+                  <span style={{ flex: 1 }}>
+                    {s.label}
+                    <span
+                      style={{
+                        marginLeft: '0.5rem',
+                        fontSize: '0.75rem',
+                        color: 'var(--color-text-3)',
+                      }}
+                    >
+                      {s.kind}
+                    </span>
+                  </span>
+                  <Badge variant={s.available ? 'lime' : 'ember'} dot>
+                    {t(
+                      s.available
+                        ? 'admin.instance.sources.available'
+                        : 'admin.instance.sources.unavailable',
+                    )}
+                  </Badge>
+                </Card>
+              ))}
+            </div>
+          )}
+        </section>
+
+        {/* ── Reindex ──────────────────────────────────────────────── */}
+        <section>
+          <h3 style={{ margin: '0 0 0.25rem', fontSize: '0.95rem' }}>
+            {t('admin.instance.reindex.title')}
+          </h3>
+          <p
+            style={{
+              margin: '0 0 0.75rem',
+              fontSize: '0.8125rem',
+              color: 'var(--color-text-3)',
+            }}
+          >
+            {t('admin.instance.reindex.description')}
+          </p>
+          {reindexMsg && (
+            <div style={{ marginBottom: '0.75rem' }}>
+              <Callout variant={reindexMsg.kind}>{reindexMsg.text}</Callout>
+            </div>
+          )}
+          <Button
+            variant="primary"
+            disabled={isReindexing}
+            onClick={() => void handleReindex()}
+          >
+            {t('admin.instance.reindex.button')}
+          </Button>
+        </section>
+      </div>
+    </Window>
+  );
 }

src/features/settings/panels.tsx

@@ -1,4 +1,5 @@
 import { useEffect, useState, type ReactNode } from 'react';
+import { useNavigate } from 'react-router';
 import { useTranslation } from 'react-i18next';
 import {
   Window,
@@ -12,6 +13,9 @@ import {
 import { SUPPORTED_LANGUAGES, setLanguage } from '../../i18n';
 import { LoadingSkeleton } from '../../components/common/LoadingSkeleton';
 import { ErrorState } from '../../components/common/ErrorState';
+import { useAppDispatch } from '../../hooks/useAppDispatch';
+import { logout } from '../../store/slices/auth';
+import { getActiveInstance } from '../../config/instances';
 import {
   useGetSettingsQuery,
   useUpdateSettingsMutation,
@@ -316,14 +320,60 @@ export function ScrobblingSettings() {
   );
 }
 
-/** `/settings/instance` — switch/forget instance. Scaffold. */
+/** `/settings/instance` — show the active instance; switch or sign out (both
+ * routes back to /connect, the full instance manager). */
 export function InstanceSettings() {
   const { t } = useTranslation();
+  const navigate = useNavigate();
+  const dispatch = useAppDispatch();
+  const instance = getActiveInstance();
+
+  const handleSignOut = () => {
+    dispatch(logout());
+    void navigate('/connect');
+  };
+
   return (
     <Window title={t('settings.tabs.instance')}>
-      <p style={{ color: 'var(--color-text-2)', margin: 0 }}>
-        {t('common.comingSoon')}
-      </p>
+      <div
+        style={{
+          padding: '0.75rem 0',
+          display: 'flex',
+          flexDirection: 'column',
+          gap: '1.25rem',
+        }}
+      >
+        <div>
+          <span style={labelStyle}>{t('settings.instance.current')}</span>
+          {instance ? (
+            <div>
+              <div style={{ fontWeight: 600 }}>{instance.name}</div>
+              <div
+                style={{
+                  fontSize: '0.8125rem',
+                  color: 'var(--color-text-3)',
+                  wordBreak: 'break-all',
+                }}
+              >
+                {instance.baseUrl}
+              </div>
+            </div>
+          ) : (
+            <p style={{ margin: 0, color: 'var(--color-text-2)' }}>
+              {t('settings.instance.none')}
+            </p>
+          )}
+        </div>
+
+        <div style={{ display: 'flex', gap: '0.5rem', flexWrap: 'wrap' }}>
+          <Button variant="ghost" onClick={() => void navigate('/connect')}>
+            {t('settings.instance.manage')}
+          </Button>
+          <Button variant="ember" onClick={handleSignOut}>
+            {t('settings.instance.signOut')}
+          </Button>
+        </div>
+      </div>
     </Window>
   );
 }

src/i18n/locales/en.ts

@@ -390,6 +390,12 @@ const en = {
       save: 'Save',
       saving: 'Saving…',
     },
+    instance: {
+      current: 'Current instance',
+      none: 'No instance selected.',
+      manage: 'Manage instances',
+      signOut: 'Sign out',
+    },
     playback: {
       streamQuality: 'Streaming quality',
       streamQualityHint:
@@ -472,6 +478,34 @@ const en = {
         cancel: 'Cancel',
       },
     },
+    instance: {
+      status: {
+        ok: 'Healthy',
+        down: 'Down',
+        skipped: 'Not configured',
+      },
+      services: {
+        title: 'Services',
+        database: 'Database',
+        redis: 'Redis',
+        ml: 'ML service',
+      },
+      sources: {
+        title: 'Sources',
+        envNote: 'Sources are configured via environment variables.',
+        empty: 'No sources configured.',
+        available: 'Available',
+        unavailable: 'Unavailable',
+      },
+      reindex: {
+        title: 'Reindex library',
+        description:
+          'Re-scan every indexable source. Runs in the background and is idempotent.',
+        button: 'Reindex',
+        enqueued: 'Reindex queued ({{count}} sources).',
+        noSource: 'No indexable source is configured.',
+      },
+    },
   },
   notFound: {
     title: 'Page not found',

src/i18n/locales/ru.ts

@@ -391,6 +391,12 @@ const ru: Translations = {
       save: 'Сохранить',
       saving: 'Сохранение…',
     },
+    instance: {
+      current: 'Текущий инстанс',
+      none: 'Инстанс не выбран.',
+      manage: 'Управление инстансами',
+      signOut: 'Выйти',
+    },
     playback: {
       streamQuality: 'Качество потока',
       streamQualityHint:
@@ -473,6 +479,34 @@ const ru: Translations = {
         cancel: 'Отмена',
       },
     },
+    instance: {
+      status: {
+        ok: 'Работает',
+        down: 'Недоступен',
+        skipped: 'Не настроен',
+      },
+      services: {
+        title: 'Сервисы',
+        database: 'База данных',
+        redis: 'Redis',
+        ml: 'ML-сервис',
+      },
+      sources: {
+        title: 'Источники',
+        envNote: 'Источники настраиваются через переменные окружения.',
+        empty: 'Источники не настроены.',
+        available: 'Доступен',
+        unavailable: 'Недоступен',
+      },
+      reindex: {
+        title: 'Переиндексация библиотеки',
+        description:
+          'Пересканировать все индексируемые источники. Выполняется в фоне, идемпотентно.',
+        button: 'Переиндексировать',
+        enqueued: 'Переиндексация запущена ({{count}} источников).',
+        noSource: 'Индексируемые источники не настроены.',
+      },
+    },
   },
   notFound: {
     title: 'Страница не найдена',