feat(layout): finalize p01 and p02 changes

Complete UI foundation and app layout implementation, stabilize container health checks, and archive both OpenSpec changes after verification.

frontend/src/routes/+layout.svelte

@@ -1,17 +1,22 @@
 <script lang="ts">
+	import { page } from '$app/stores';
+	import AppLayout from '$lib/components/layout/AppLayout.svelte';
 	import { initAuth } from '$lib/stores/auth';
-	import Navigation from '$lib/components/Navigation.svelte';
+	import '$lib/stores/layout';
 	import { onMount } from 'svelte';
 
+	const publicPages = ['/login', '/auth'];
+	$: shouldUseAppLayout = !publicPages.some((path) => $page.url.pathname.startsWith(path));
+
 	onMount(() => {
 		initAuth();
 	});
 </script>
 
-<div class="min-h-screen bg-base-200">
-	<Navigation />
-	
-	<main class="container mx-auto px-4 py-6">
+{#if shouldUseAppLayout}
+	<AppLayout>
 		<slot />
-	</main>
-</div>
+	</AppLayout>
+{:else}
+	<slot />
+{/if}