feat: add fullscreen QR code for subscription connection

- New ConnectionQR page with fullscreen QR display (no modal)
- QR button in InstallationGuide header next to platform selector
- Respects hideLink setting: shows URL below QR only when visible
- i18n translations for ru, en, zh, fa

src/App.tsx

@@ -35,6 +35,7 @@ const Polls = lazy(() => import('./pages/Polls'));
 const Info = lazy(() => import('./pages/Info'));
 const Wheel = lazy(() => import('./pages/Wheel'));
 const Connection = lazy(() => import('./pages/Connection'));
+const ConnectionQR = lazy(() => import('./pages/ConnectionQR'));
 const TopUpMethodSelect = lazy(() => import('./pages/TopUpMethodSelect'));
 const TopUpAmount = lazy(() => import('./pages/TopUpAmount'));
 
@@ -322,6 +323,14 @@ function App() {
             </ProtectedRoute>
           }
         />
+        <Route
+          path="/connection/qr"
+          element={
+            <LazyPage>
+              <ConnectionQR />
+            </LazyPage>
+          }
+        />
         <Route
           path="/connection"
           element={