feat(web): storage admin, search and catalog pages (M2)

- Storage admin: local folders with a folder picker and NFS sources,
  connection test, scan and full scan with live progress, enable,
  disable, delete
- path pattern editor with reorder, examples and a preview table that
  shows which pattern matched and what came from tags; compile errors
  land under the broken pattern
- Library page with counters, scans and unreadable files; search
  reindex for admins
- search box in the top bar: combobox with keyboard navigation, 150 ms
  debounce, cancelled stale requests, "/" and Ctrl+K, layout fix hint
- search page with tabs and paging, artist and album pages, album
  cards and track lists; unavailable tracks are dimmed

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/web/src/pages/ArtistPage.tsx

@@ -0,0 +1,57 @@
+import { unwrap } from '@pipu/core';
+import { useQuery } from '@tanstack/react-query';
+import { useTranslation } from 'react-i18next';
+
+import { useSession } from '../app/session';
+import { AlbumGrid, Cover } from '../entities/catalog';
+import { NotFound } from './NotFound';
+import s from './page.module.css';
+import c from './catalog.module.css';
+
+export function ArtistPage({ id }: { id: string }) {
+  const { t } = useTranslation();
+  const session = useSession();
+  const artist = useQuery({
+    queryKey: ['artist', id],
+    queryFn: async () => unwrap(await session.client.GET('/api/v1/artists/{id}', { params: { path: { id } } })),
+  });
+  const albums = useQuery({
+    queryKey: ['artist-albums', id],
+    queryFn: async () =>
+      unwrap(await session.client.GET('/api/v1/artists/{id}/albums', { params: { path: { id } } })).items,
+  });
+
+  if (artist.isError) return <NotFound error={artist.error} />;
+  const a = artist.data;
+  const own = albums.data?.filter((al) => al.artist.id === id) ?? [];
+  const appears = albums.data?.filter((al) => al.artist.id !== id) ?? [];
+
+  return (
+    <div className={s.page}>
+      <header className={c.hero}>
+        <Cover album={{ id }} size={168} round />
+        <div className={c.heroBody}>
+          <span className={c.kind}>{t('catalog.artist')}</span>
+          <h1 className={c.heroTitle}>{a?.name ?? '…'}</h1>
+          {a && (
+            <span className={c.heroMeta}>
+              {t('catalog.album_count', { count: a.album_count })} · {t('catalog.track_count', { count: a.track_count })}
+            </span>
+          )}
+        </div>
+      </header>
+      {own.length > 0 && (
+        <section className={c.section}>
+          <h2>{t('catalog.albums')}</h2>
+          <AlbumGrid albums={own} />
+        </section>
+      )}
+      {appears.length > 0 && (
+        <section className={c.section}>
+          <h2>{t('catalog.appears_on')}</h2>
+          <AlbumGrid albums={appears} />
+        </section>
+      )}
+    </div>
+  );
+}