feat: add booklet viewer i18n keys to all 4 locales

src/lib/i18n/locales/de.json

@@ -227,7 +227,12 @@
     "saveAs": "Speichern unter...",
     "customCoverSet": "Albumcover aktualisiert",
     "customCoverRemoved": "Benutzerdefiniertes Albumcover entfernt",
-    "customCoverError": "Fehler beim Aktualisieren des Albumcovers"
+    "customCoverError": "Fehler beim Aktualisieren des Albumcovers",
+    "booklet": "Booklet",
+    "viewBooklet": "Booklet anzeigen",
+    "bookletLoading": "Booklet wird geladen...",
+    "bookletError": "Booklet konnte nicht geladen werden",
+    "bookletFitWidth": "An Breite anpassen"
   },
   "artist": {
     "albums": "Alben",

src/lib/i18n/locales/en.json

@@ -239,7 +239,12 @@
     "saveAs": "Save as...",
     "customCoverSet": "Album cover updated",
     "customCoverRemoved": "Custom album cover removed",
-    "customCoverError": "Failed to update album cover"
+    "customCoverError": "Failed to update album cover",
+    "booklet": "Booklet",
+    "viewBooklet": "View Booklet",
+    "bookletLoading": "Loading booklet...",
+    "bookletError": "Could not load booklet",
+    "bookletFitWidth": "Fit to width"
   },
   "artist": {
     "albums": "Albums",

src/lib/i18n/locales/es.json

@@ -239,7 +239,12 @@
     "saveAs": "Guardar como...",
     "customCoverSet": "Portada del album actualizada",
     "customCoverRemoved": "Portada personalizada eliminada",
-    "customCoverError": "Error al actualizar la portada"
+    "customCoverError": "Error al actualizar la portada",
+    "booklet": "Libreto",
+    "viewBooklet": "Ver libreto",
+    "bookletLoading": "Cargando libreto...",
+    "bookletError": "No se pudo cargar el libreto",
+    "bookletFitWidth": "Ajustar al ancho"
   },
   "artist": {
     "albums": "Álbumes",

src/lib/i18n/locales/fr.json

@@ -227,7 +227,12 @@
     "saveAs": "Enregistrer sous...",
     "customCoverSet": "Pochette de l'album mise à jour",
     "customCoverRemoved": "Pochette personnalisée supprimée",
-    "customCoverError": "Erreur lors de la mise à jour de la pochette"
+    "customCoverError": "Erreur lors de la mise à jour de la pochette",
+    "booklet": "Livret",
+    "viewBooklet": "Voir le livret",
+    "bookletLoading": "Chargement du livret...",
+    "bookletError": "Impossible de charger le livret",
+    "bookletFitWidth": "Ajuster à la largeur"
   },
   "artist": {
     "albums": "Albums",