feat(start): recent files as a list, icons or large previews

Three toggles beside the Recent Documents title switch the panel between
the existing list, a grid of thumbnail tiles and one large preview per
file. The choice is kept in the recent section of the app config.

Refs #1494

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

locales/es-ES/opencadstudio.ftl

@@ -99,6 +99,9 @@ start =
     .no-recent-files = Los archivos que abra aparecerán aquí.
     .browser-storage = Almacenamiento del navegador
     .keep-recent-files = Conservar archivos recientes
+    .view-list = Lista
+    .view-icons = Iconos
+    .view-preview = Vistas previas grandes
 
 donation =
     .title = Solicitud de donación