add easter egg and settings menu

src/lib/stores.ts

@@ -1,5 +1,4 @@
-import { type Writable, writable } from 'svelte/store';
+import { persisted } from 'svelte-local-storage-store';
+import type { Writable } from 'svelte/store';
 
-export const registered: Writable<{
-	username: string;
-} | null> = writable(null);
+export const playAudio: Writable<boolean> = persisted('playAudio', false);