Close remaining visual gaps: tile icons, gradient, third tab, popular styling

Enable flights-map tab by default (showFlightsMap=true) to match Angular
production config where flightsMap feature flag is true. The other three
items (tile icons, body background, popular-requests panel) were already
ported identically in the React SCSS.

src/ui/layout/PageTabs.tsx

@@ -19,7 +19,7 @@ export interface PageTabsProps {
 
 export const PageTabs: FC<PageTabsProps> = ({
   viewType,
-  showFlightsMap = false,
+  showFlightsMap = true,
 }) => {
   const { t } = useTranslation();
   const routeParams = useParams<{ lang: string }>();