Add Footer component to FlagQuiz and Game pages for consistent layout

src/pages/FlagQuiz.svelte

@@ -1,6 +1,7 @@
 <script>
   import { onMount } from 'svelte';
   import Header from '../components/Header.svelte';
+  import Footer from '../components/Footer.svelte';
   import InlineSvg from '../components/InlineSvg.svelte';
   import Achievements from '../components/Achievements.svelte';
   import AchievementButton from '../components/AchievementButton.svelte';
@@ -703,6 +704,8 @@
     </div>
 </main>
 
+<Footer />
+
 <style>
   .flag-quiz {
     min-height: 100vh;