Restore compact Changes diff controls (#1945)

* feat(app): restore compact Changes diff controls

Keep the folder tree behind a view toggle while preserving the flat file list as the default.

Move secondary diff options into the overflow menu so the Changes toolbar stays compact.

* fix(app): mirror whitespace diff option copy

* fix(app): polish diff controls review follow-up

packages/app/src/i18n/resources/fr.ts

@@ -733,7 +733,13 @@ export const fr: TranslationResources = {
         tooLarge: "Diff trop grand pour être affiché",
         unified: "Différentiel unifié",
         split: "Différent côte à côte",
+        switchToUnified: "Passer au diff unifié",
+        switchToSplit: "Passer au diff côte à côte",
+        showTreeView: "Afficher l'arborescence des dossiers",
+        showFlatView: "Afficher la liste de fichiers à plat",
+        options: "Options du diff",
         hideWhitespace: "Masquer les espaces",
+        showWhitespace: "Afficher les espaces",
         scrollLongLines: "Faire défiler les longues lignes",
         wrapLongLines: "Enroulez les longues lignes",
         collapseAll: "Réduire tous les fichiers",