feat(authors): rebuild the page as an index and a gallery on one view toggle

The two layouts are the viewMode the app already persists, so search, filters
and sort carry across them. Only 19% of a library's authors have a portrait,
so the gallery leans on monograms and the index treats the name as the content;
a sort name now prints only when it says something the display name does not.
Jump buckets, a cover fallback and two filters come from the server so the A-Z
rail and the chips cover the whole result set rather than the loaded pages.

Reconciles authors.has_photo against the image store on boot: the list resolves
portraits from disk while the filter queried the column, so "no portrait" was
over-reporting by 64.

client/src/locales/pt.json

@@ -3233,19 +3233,8 @@
       "refreshMetadata": "Atualizar Metadados",
       "deleteAuthor": "Excluir Autor"
     },
-    "listRow": {
-      "noRecentAdditions": "Nenhuma adição recente",
-      "portraitAlt": "Retrato de {name}"
-    },
     "filters": {
-      "title": "Filtros de Autores",
-      "clearAll": "Limpar tudo",
-      "allLibraries": "Todas as Bibliotecas",
-      "allAuthors": "Todos os autores",
-      "hasPhoto": "Com foto",
-      "missingPhoto": "Sem foto",
-      "minBooks": "Mínimo de livros",
-      "anyPlaceholder": "Qualquer"
+      "allLibraries": "Todas as Bibliotecas"
     },
     "header": {
       "never": "Nunca",