fix(hub): a track with no artist tag reaches the Music grid

The grid's unit is an album, so a track whose artist tag is empty was
drawn nowhere — while `empty` counted it and stayed false, so no message
appeared either. An untagged library rendered a toolbar over a blank
page, with every track one mode-switch away and nothing saying so.

It gets a card, the same shape the singleton folding already mints. No
cover is looked up for it, or for any album this file invented: the
release name is one the browser wrote, and the request cannot match.

music_untagged_probe.py renders the real grid and reads the page back.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

11 files changed, 45 insertions, 4 deletions

diff --git a/packages/meshbay-hub/src/meshbay_hub/static/locales/de.js b/packages/meshbay-hub/src/meshbay_hub/static/locales/de.js
index 2d925e1..aea1196 100644
--- a/packages/meshbay-hub/src/meshbay_hub/static/locales/de.js
+++ b/packages/meshbay-hub/src/meshbay_hub/static/locales/de.js
@@ -302,6 +302,7 @@ export default {
   'music.mode_flat': 'Flache Liste',
   'music.empty': 'Keine Musik gefunden.',
   'music.unknown_album': 'Unbekanntes Album',
+  'music.unknown_artist': 'Unbekannter Künstler',
   'music.various': 'Verschiedenes',
   'music.play_all': 'Alle abspielen',
   'music.menu_more': 'Mehr…',
diff --git a/packages/meshbay-hub/src/meshbay_hub/static/locales/en.js b/packages/meshbay-hub/src/meshbay_hub/static/locales/en.js
index 690a70b..d9172a6 100644
--- a/packages/meshbay-hub/src/meshbay_hub/static/locales/en.js
+++ b/packages/meshbay-hub/src/meshbay_hub/static/locales/en.js
@@ -300,6 +300,7 @@ export default {
   'music.mode_flat': 'Flat list',
   'music.empty': 'No music found.',
   'music.unknown_album': 'Unknown album',
+  'music.unknown_artist': 'Unknown artist',
   'music.various': 'Various',
   'music.play_all': 'Play all',
   'music.menu_more': 'More…',
diff --git a/packages/meshbay-hub/src/meshbay_hub/static/locales/es.js b/packages/meshbay-hub/src/meshbay_hub/static/locales/es.js
index c48f942..fc0e639 100644
--- a/packages/meshbay-hub/src/meshbay_hub/static/locales/es.js
+++ b/packages/meshbay-hub/src/meshbay_hub/static/locales/es.js
@@ -300,6 +300,7 @@ export default {
   'music.mode_flat': 'Lista plana',
   'music.empty': 'No se encontró música.',
   'music.unknown_album': 'Álbum desconocido',
+  'music.unknown_artist': 'Artista desconocido',
   'music.various': 'Varios',
   'music.play_all': 'Reproducir todo',
   'music.menu_more': 'Más…',
diff --git a/packages/meshbay-hub/src/meshbay_hub/static/locales/fr.js b/packages/meshbay-hub/src/meshbay_hub/static/locales/fr.js
index 6d148d6..5eb8d60 100644
--- a/packages/meshbay-hub/src/meshbay_hub/static/locales/fr.js
+++ b/packages/meshbay-hub/src/meshbay_hub/static/locales/fr.js
@@ -301,6 +301,7 @@ export default {
   'music.mode_flat': 'Liste à plat',
   'music.empty': 'Aucune musique trouvée.',
   'music.unknown_album': 'Album inconnu',
+  'music.unknown_artist': 'Artiste inconnu',
   'music.various': 'Divers',
   'music.play_all': 'Tout lire',
   'music.menu_more': 'Plus…',
diff --git a/packages/meshbay-hub/src/meshbay_hub/static/locales/it.js b/packages/meshbay-hub/src/meshbay_hub/static/locales/it.js
index c619d61..6d12cb3 100644
--- a/packages/meshbay-hub/src/meshbay_hub/static/locales/it.js
+++ b/packages/meshbay-hub/src/meshbay_hub/static/locales/it.js
@@ -301,6 +301,7 @@ export default {
   'music.mode_flat': 'Elenco semplice',
   'music.empty': 'Nessuna musica trovata.',
   'music.unknown_album': 'Album sconosciuto',
+  'music.unknown_artist': 'Artista sconosciuto',
   'music.various': 'Vari',
   'music.play_all': 'Riproduci tutto',
   'music.menu_more': 'Altro…',
diff --git a/packages/meshbay-hub/src/meshbay_hub/static/locales/ja.js b/packages/meshbay-hub/src/meshbay_hub/static/locales/ja.js
index eac90dc..f4ced88 100644
--- a/packages/meshbay-hub/src/meshbay_hub/static/locales/ja.js
+++ b/packages/meshbay-hub/src/meshbay_hub/static/locales/ja.js
@@ -298,6 +298,7 @@ export default {
   'music.mode_flat': 'フラットリスト',
   'music.empty': '音楽が見つかりません。',
   'music.unknown_album': '不明なアルバム',
+  'music.unknown_artist': '不明なアーティスト',
   'music.various': 'その他',
   'music.play_all': 'すべて再生',
   'music.menu_more': 'その他…',
diff --git a/packages/meshbay-hub/src/meshbay_hub/static/locales/nl.js b/packages/meshbay-hub/src/meshbay_hub/static/locales/nl.js
index 65bf4f5..31a2321 100644
--- a/packages/meshbay-hub/src/meshbay_hub/static/locales/nl.js
+++ b/packages/meshbay-hub/src/meshbay_hub/static/locales/nl.js
@@ -302,6 +302,7 @@ export default {
   'music.mode_flat': 'Platte lijst',
   'music.empty': 'Geen muziek gevonden.',
   'music.unknown_album': 'Onbekend album',
+  'music.unknown_artist': 'Onbekende artiest',
   'music.various': 'Diversen',
   'music.play_all': 'Alles afspelen',
   'music.menu_more': 'Meer…',
diff --git a/packages/meshbay-hub/src/meshbay_hub/static/locales/pl.js b/packages/meshbay-hub/src/meshbay_hub/static/locales/pl.js
index 264d442..463a6a9 100644
--- a/packages/meshbay-hub/src/meshbay_hub/static/locales/pl.js
+++ b/packages/meshbay-hub/src/meshbay_hub/static/locales/pl.js
@@ -309,6 +309,7 @@ export default {
   'music.mode_flat': 'Lista płaska',
   'music.empty': 'Nie znaleziono muzyki.',
   'music.unknown_album': 'Nieznany album',
+  'music.unknown_artist': 'Nieznany wykonawca',
   'music.various': 'Różne',
   'music.play_all': 'Odtwórz wszystko',
   'music.menu_more': 'Więcej…',
diff --git a/packages/meshbay-hub/src/meshbay_hub/static/locales/pt-BR.js b/packages/meshbay-hub/src/meshbay_hub/static/locales/pt-BR.js
index 0fbfb1e..20822ee 100644
--- a/packages/meshbay-hub/src/meshbay_hub/static/locales/pt-BR.js
+++ b/packages/meshbay-hub/src/meshbay_hub/static/locales/pt-BR.js
@@ -302,6 +302,7 @@ export default {
   'music.mode_flat': 'Lista simples',
   'music.empty': 'Nenhuma música encontrada.',
   'music.unknown_album': 'Álbum desconhecido',
+  'music.unknown_artist': 'Artista desconhecido',
   'music.various': 'Diversos',
   'music.play_all': 'Reproduzir tudo',
   'music.menu_more': 'Mais…',
diff --git a/packages/meshbay-hub/src/meshbay_hub/static/locales/zh-CN.js b/packages/meshbay-hub/src/meshbay_hub/static/locales/zh-CN.js
index ab75b11..b2d7591 100644
--- a/packages/meshbay-hub/src/meshbay_hub/static/locales/zh-CN.js
+++ b/packages/meshbay-hub/src/meshbay_hub/static/locales/zh-CN.js
@@ -295,6 +295,7 @@ export default {
   'music.mode_flat': '平铺列表',
   'music.empty': '未找到音乐。',
   'music.unknown_album': '未知专辑',
+  'music.unknown_artist': '未知艺术家',
   'music.various': '其他',
   'music.play_all': '全部播放',
   'music.menu_more': '更多…',
diff --git a/packages/meshbay-hub/src/meshbay_hub/static/music-app.js b/packages/meshbay-hub/src/meshbay_hub/static/music-app.js
index e0308cb..1dbecbb 100644
--- a/packages/meshbay-hub/src/meshbay_hub/static/music-app.js
+++ b/packages/meshbay-hub/src/meshbay_hub/static/music-app.js
@@ -256,7 +256,13 @@ function AlbumCard({ album, transportRef, gekRef, musicbrainzEnabled, onOpen, on
   const repTrack = album.tracks.find((tr) => tr.thumb_hash) || album.tracks[0];
   const tRef = repTrack._tRef || transportRef;
   const gRef = repTrack._gRef || gekRef;
-  const needsLookup = musicbrainzEnabled && !repTrack.thumb_hash;
+  // Never for an album this file minted itself (`isUnknown`): the release
+  // name is one we wrote -- '<artist> - Various', or the untagged pile
+  // below -- so the lookup is a third-party request, on the operator's
+  // connection, that cannot match anything. Confirmed in a node's log:
+  // queries went out naming a placeholder as both the artist and the
+  // release, once per card.
+  const needsLookup = musicbrainzEnabled && !repTrack.thumb_hash && !album.isUnknown;
   const meta = useMusicMeta(tRef, repTrack.id, needsLookup);
   const coverHash = repTrack.thumb_hash || (meta && meta.cover_thumb_hash) || null;
 
@@ -287,7 +293,7 @@ function MusicDetailModal({ album, transportRef, gekRef, musicbrainzEnabled, onC
   const repTrack = album.tracks.find((tr) => tr.thumb_hash) || album.tracks[0];
   const tRef = repTrack._tRef || transportRef;
   const gRef = repTrack._gRef || gekRef;
-  const needsLookup = musicbrainzEnabled && !repTrack.thumb_hash;
+  const needsLookup = musicbrainzEnabled && !repTrack.thumb_hash && !album.isUnknown;
   const meta = useMusicMeta(tRef, repTrack.id, needsLookup);
   const coverHash = repTrack.thumb_hash || (meta && meta.cover_thumb_hash) || null;
 
@@ -672,17 +678,39 @@ function MusicApp({
   const filteredTracks = useMemo(() => (!needle ? tracks : tracks.filter(
     (tr) => (tr.display_title || tr.name).toLowerCase().includes(needle))), [tracks, needle]);
 
+  // A track whose artist tag is empty *and* whose folder gave nothing to fall
+  // back on. The flat list has always drawn these as its own top-level rows;
+  // the grid, whose unit is an album, drew them nowhere at all -- and `empty`
+  // below counts them, so it stayed false and no message appeared either. A
+  // library nothing has tagged therefore rendered a toolbar over a blank page,
+  // with every one of its tracks one mode-switch away and nothing saying so.
+  // Reported after a node restart, where the index is briefly served without
+  // the tags it re-reads at start-up, and true of a genuinely untagged library
+  // with no restart involved.
+  //
+  // One card, the same shape the singleton folding above already mints for an
+  // artist's leftovers: it names what it is, and the tracks are playable from
+  // it. Not a card each -- that is the wall of one-track tiles this file
+  // exists to avoid -- and not sorted in among the artists, because it is not
+  // a name anybody chose and the alphabet is no place for it.
+  const untagged = useMemo(() => (filteredTracks.length
+    ? { artist: t('music.unknown_artist'), album: t('music.unknown_album'),
+        isUnknown: true, tracks: filteredTracks }
+    : null), [filteredTracks]);
+
   // What this mode draws, in drawing order: albums under their artists in the
   // grid, and in the flat list loose tracks and artist folders sorted together.
   const units = useMemo(() => {
     if (mode === 'grid') {
-      return filteredArtists.flatMap((a) => a.albums.map((album) => ({ artist: a.artist, album })));
+      const byArtist = filteredArtists.flatMap(
+        (a) => a.albums.map((album) => ({ artist: a.artist, album })));
+      return untagged ? [...byArtist, { artist: untagged.artist, album: untagged }] : byArtist;
     }
     return [
       ...filteredTracks.map((tr) => ({ key: tr.display_title || tr.name, kind: 'track', track: tr })),
       ...filteredArtists.map((a) => ({ key: a.artist, kind: 'artist', artist: a })),
     ].sort((a, b) => a.key.localeCompare(b.key));
-  }, [mode, filteredArtists, filteredTracks]);
+  }, [mode, filteredArtists, filteredTracks, untagged]);
 
   const pager = usePager(units.length, pageSizeFrom(userPrefs),
     `${groupId}|${mode}|${needle}|${pageResetKey || ''}`);
@@ -690,6 +718,9 @@ function MusicApp({
     return units.slice(pager.start, pager.end);
   }, [units, pager.start, pager.end]);
 
+  // True exactly when the library has nothing, and — now that every track
+  // reaches a card — exactly when the grid has nothing to draw either. The two
+  // used to disagree, which is the whole of the defect above.
   const empty = albums.length === 0 && tracks.length === 0;
 
   return html`