✅(frontend) keep translations in sync across languages

Several keys were missing in some languages (Dutch search filters,
delete menu labels, restore toasts, file picker caption), silently
falling back to English. Sync them and add a test failing whenever a
key exists in one language but not the others, so gaps are caught at
review time instead of in production.

src/frontend/apps/drive/src/features/i18n/__tests__/translations.test.ts

@@ -0,0 +1,56 @@
+import translations from "../translations.json";
+
+type TranslationNode = { [key: string]: string | TranslationNode };
+
+const flattenKeys = (node: TranslationNode, prefix = ""): string[] => {
+  return Object.entries(node).flatMap(([key, value]) => {
+    const path = prefix ? `${prefix}.${key}` : key;
+    return typeof value === "string" ? [path] : flattenKeys(value, path);
+  });
+};
+
+const flattenEntries = (
+  node: TranslationNode,
+  prefix = ""
+): [string, string][] => {
+  return Object.entries(node).flatMap(([key, value]) => {
+    const path = prefix ? `${prefix}.${key}` : key;
+    return typeof value === "string"
+      ? ([[path, value]] as [string, string][])
+      : flattenEntries(value, path);
+  });
+};
+
+const languages = Object.keys(translations) as (keyof typeof translations)[];
+
+describe("translations.json", () => {
+  it("declares the same keys in every language", () => {
+    const keysByLanguage = Object.fromEntries(
+      languages.map((language) => [
+        language,
+        flattenKeys(translations[language].translation).sort(),
+      ])
+    );
+
+    for (const language of languages) {
+      // Compared pairwise against every other language so the failure
+      // diff shows exactly which keys are missing on which side.
+      for (const other of languages) {
+        const missing = keysByLanguage[language].filter(
+          (key) => !keysByLanguage[other].includes(key)
+        );
+        expect({ language: other, missing }).toEqual({
+          language: other,
+          missing: [],
+        });
+      }
+    }
+  });
+
+  it.each(languages)("has no empty values in %s", (language) => {
+    const empty = flattenEntries(translations[language].translation)
+      .filter(([, value]) => value.trim() === "")
+      .map(([key]) => key);
+    expect(empty).toEqual([]);
+  });
+});

src/frontend/apps/drive/src/features/i18n/translations.json

@@ -376,6 +376,9 @@
               "settings_workspace": "Workspace settings",
               "settings_folder": "Folder settings",
               "delete_item": "Delete",
+              "delete_workspace": "Delete workspace",
+              "delete_folder": "Delete folder",
+              "delete_file": "Delete file",
               "share": "Share",
               "share_view": "View shares"
             },
@@ -560,6 +563,10 @@
             "toast_one": "Item deleted forever",
             "toast_other": "{{count}} items deleted forever"
           },
+          "restore": {
+            "toast_one": "Item restored",
+            "toast_other": "{{count}} items restored"
+          },
           "move": {
             "toast_one": "{{count}} item moved",
             "toast_other": "{{count}} items moved",
@@ -641,6 +648,7 @@
         "explorer": {
           "cancel": "Cancel",
           "choose": "Choose",
+          "picker_caption": "Select one or more files",
           "picker_label_zero": "No files selected",
           "picker_label_one": "{{count}} file selected",
           "picker_label_other": "{{count}} files selected",
@@ -1698,6 +1706,15 @@
           }
         },
         "filters": {
+          "location": {
+            "label": "Locatie",
+            "options": {
+              "my_files": "Mijn bestanden",
+              "shared_with_me": "Gedeeld met mij",
+              "starred": "Favorieten",
+              "trashbin": "Prullenbak"
+            }
+          },
           "scopes": {
             "label": "Locatie",
             "options": {
@@ -1714,6 +1731,39 @@
               "reset": "Reset"
             }
           },
+          "category": {
+            "label": "Type",
+            "options": {
+              "doc": "Tekstdocument",
+              "powerpoint": "Presentatie",
+              "calc": "Spreadsheet",
+              "pdf": "PDF",
+              "image": "Afbeelding",
+              "video": "Video",
+              "audio": "Audio",
+              "archive": "Archief",
+              "other": "Overig"
+            }
+          },
+          "contact": {
+            "label": "Gedeeld met",
+            "placeholder": "Zoek een naam",
+            "empty": "Geen contacten gevonden",
+            "reset": "Opnieuw instellen"
+          },
+          "modified": {
+            "label": "Gewijzigd",
+            "options": {
+              "today": "Vandaag",
+              "last_7_days": "Laatste 7 dagen",
+              "last_30_days": "Laatste 30 dagen",
+              "this_year": "Dit jaar",
+              "more_than_a_year": "Meer dan een jaar geleden",
+              "custom": "Aangepaste periode"
+            },
+            "start": "Begin",
+            "end": "Einde"
+          },
           "workspace": {
             "label": "Werkruimte"
           },
@@ -1744,6 +1794,9 @@
               "settings_workspace": "Werkruimte instellingen",
               "settings_folder": "Map instellingen",
               "delete_item": "Verwijder",
+              "delete_workspace": "Ruimte verwijderen",
+              "delete_folder": "Map verwijderen",
+              "delete_file": "Bestand verwijderen",
               "share": "Deel",
               "share_view": "Bekijk delen"
             },
@@ -1928,6 +1981,10 @@
             "toast_one": "Item permanent verwijderd",
             "toast_other": "{{count}} items permanent verwijderd"
           },
+          "restore": {
+            "toast_one": "Item hersteld",
+            "toast_other": "{{count}} items hersteld"
+          },
           "move": {
             "toast_one": "{{count}} item verplaatst",
             "toast_other": "{{count}} items verplaatst",
@@ -1990,7 +2047,6 @@
         "copy_link": "Kopieer link",
         "languages": "Talen"
       },
- 
       "time": {
         "years_ago_one": "{{count}} jaar geleden",
         "years_ago_other": "{{count}} jaren geleden",
@@ -2010,6 +2066,7 @@
         "explorer": {
           "choose": "Kiezen",
           "cancel": "Annuleren",
+          "picker_caption": "Selecteer een of meerdere bestanden",
           "picker_label_zero": "Geen bestanden geselecteerd",
           "picker_label_one": "{{count}} bestand geselecteerd",
           "picker_label_other": "{{count}} bestanden geselecteerd",