feat(landing): VK entry logo + restore the Telegram channel build-arg

Add the VK Mini App logo next to the Telegram one on the landing hero,
linked via the new VITE_VK_APP_LINK build-arg (full URL, wired through
compose, CI and prod-deploy from TEST_/PROD_VITE_VK_APP_LINK).

Also restore the landing's Telegram link itself: commit 57c778f
collapsed the per-language vars to VITE_TELEGRAM_GAME_CHANNEL_NAME in
compose/CI but left gateway/Dockerfile with the stale _EN/_RU ARGs and
without the plain one, so the built bundle saw the var as undefined and
dead-code-eliminated the whole channel-link branch — deployed landings
(prod included) have shown no Telegram logo since.

ui/src/lib/i18n/en.ts

@@ -205,6 +205,7 @@ export const en = {
 
   'landing.tagline': 'Play Scrabble with friends or a smart robot — in your browser or on Telegram.',
   'landing.playTelegram': 'Play in Telegram',
+  'landing.playVK': 'Play on VK',
 
   'lang.en': 'English',
   'lang.ru': 'Русский',

ui/src/lib/i18n/ru.ts

@@ -205,6 +205,7 @@ export const ru: Record<MessageKey, string> = {
 
   'landing.tagline': 'Играй в Скрэббл с друзьями или умным роботом — в браузере или в Telegram.',
   'landing.playTelegram': 'Играть в Telegram',
+  'landing.playVK': 'Играть во ВКонтакте',
 
   'lang.en': 'English',
   'lang.ru': 'Русский',

ui/src/lib/landing.test.ts

@@ -1,5 +1,5 @@
 import { afterEach, describe, expect, it, vi } from 'vitest';
-import { telegramChannelLink } from './landing';
+import { telegramChannelLink, vkAppLink } from './landing';
 
 describe('telegramChannelLink', () => {
   afterEach(() => vi.unstubAllEnvs());
@@ -14,3 +14,17 @@ describe('telegramChannelLink', () => {
     expect(telegramChannelLink()).toBeNull();
   });
 });
+
+describe('vkAppLink', () => {
+  afterEach(() => vi.unstubAllEnvs());
+
+  it('returns the configured VK app link verbatim', () => {
+    vi.stubEnv('VITE_VK_APP_LINK', 'https://vk.com/app54655464');
+    expect(vkAppLink()).toBe('https://vk.com/app54655464');
+  });
+
+  it('returns null when the link is unset or blank', () => {
+    vi.stubEnv('VITE_VK_APP_LINK', '   ');
+    expect(vkAppLink()).toBeNull();
+  });
+});

ui/src/lib/landing.ts

@@ -1,5 +1,5 @@
 // Pure helpers for the public landing page, kept out of the Svelte component so the
-// Telegram-channel link selection is unit-testable.
+// platform-entry link selection is unit-testable.
 
 /**
  * telegramChannelLink returns the t.me link for the single bot's game channel, or null
@@ -13,3 +13,15 @@ export function telegramChannelLink(): string | null {
   const name = (raw as string | undefined)?.trim().replace(/^@/, '');
   return name ? `https://t.me/${name}` : null;
 }
+
+/**
+ * vkAppLink returns the VK Mini App link for the landing "Play on VK" entry, or null when it is
+ * not configured. The link is a build-time var (VITE_VK_APP_LINK, the full URL
+ * `https://vk.com/app<id>`) because the test and prod contours run the same VK app but the var
+ * mirrors the per-contour Telegram entries.
+ */
+export function vkAppLink(): string | null {
+  const raw = import.meta.env.VITE_VK_APP_LINK;
+  const link = (raw as string | undefined)?.trim();
+  return link ? link : null;
+}