fix(i18n): the video menu's download row says "Download…", and counted copy is pluralized

- The row opens the download dialog, so it is labelled so; the download's state ("Downloaded",
  "In queue") is its hint, not its label.
- The share dialog's expiry ("1 days") and a link's view count ("1 views") go through i18next's
  plural forms (`count`).

frontend/src/i18n/locales/en/downloads.json

@@ -1,5 +1,8 @@
 {
   "navLabel": "Downloads",
+  "menu": {
+    "download": "Download…"
+  },
   "button": {
     "label": "Download",
     "queued": "In queue",
@@ -124,13 +127,15 @@
     "allowDownload": "Allow download",
     "expiry": "Expires",
     "expiryNever": "Never",
-    "days": "{{n}} days",
+    "days_one": "{{count}} day",
+    "days_other": "{{count}} days",
     "password": "Password (optional)",
     "copy": "Copy link",
     "copyFailed": "Couldn’t copy",
     "revoke": "Revoke",
     "revokeConfirm": "This link will stop working immediately.",
-    "views": "{{n}} views",
+    "views_one": "{{count}} view",
+    "views_other": "{{count}} views",
     "expiresOn": "expires {{date}}",
     "hasPassword": "password",
     "downloadable": "downloadable",

frontend/src/i18n/locales/hu/downloads.json

@@ -1,5 +1,8 @@
 {
   "navLabel": "Letöltések",
+  "menu": {
+    "download": "Letöltés…"
+  },
   "button": {
     "label": "Letöltés",
     "queued": "Sorban",
@@ -124,13 +127,15 @@
     "allowDownload": "Letöltés engedélyezése",
     "expiry": "Lejárat",
     "expiryNever": "Soha",
-    "days": "{{n}} nap",
+    "days_one": "{{count}} nap",
+    "days_other": "{{count}} nap",
     "password": "Jelszó (opcionális)",
     "copy": "Link másolása",
     "copyFailed": "Nem sikerült másolni",
     "revoke": "Visszavonás",
     "revokeConfirm": "A link azonnal használhatatlanná válik.",
-    "views": "{{n}} megtekintés",
+    "views_one": "{{count}} megtekintés",
+    "views_other": "{{count}} megtekintés",
     "expiresOn": "lejár: {{date}}",
     "hasPassword": "jelszó",
     "downloadable": "letölthető",

frontend/src/i18n/plurals.test.ts

@@ -0,0 +1,24 @@
+// @vitest-environment jsdom
+//
+// E28 review J5: a count in copy goes through i18next's plural forms (`count`), never a bare `n` —
+// the share dialog's expiry read "1 days".
+import { describe, expect, it } from "vitest";
+
+import i18n from "./index";
+
+describe("counted copy", () => {
+  it("the share link's expiry is singular for one day", async () => {
+    await i18n.changeLanguage("en");
+    expect(i18n.t("downloads.share.days", { count: 1 })).toBe("1 day");
+    expect(i18n.t("downloads.share.days", { count: 7 })).toBe("7 days");
+    await i18n.changeLanguage("hu");
+    expect(i18n.t("downloads.share.days", { count: 1 })).toBe("1 nap");
+    await i18n.changeLanguage("en");
+  });
+
+  it("a link's view count is singular for one view", async () => {
+    await i18n.changeLanguage("en");
+    expect(i18n.t("downloads.share.views", { count: 1 })).toBe("1 view");
+    expect(i18n.t("downloads.share.views", { count: 0 })).toBe("0 views");
+  });
+});