feat(frontend): add stealth overlay

frontend/src/routes/[mnemonic]/+page.svelte

@@ -7,6 +7,7 @@
 	import ChatMessage from '$lib/components/ChatMessage.svelte';
 	import ChatInput from '$lib/components/ChatInput.svelte';
 	import FollowUpButtons from '$lib/components/FollowUpButtons.svelte';
+	import StealthOverlay from '$lib/components/StealthOverlay.svelte';
 
 	const usePolling = getContext<boolean>('convex-use-polling') ?? false;
 	let mnemonic = $derived(page.params.mnemonic);
@@ -185,4 +186,6 @@
 			↓
 		</button>
 	{/if}
+
+	<StealthOverlay />
 </div>