Add ModeTemplate with Svelte 5 frontend and components

- Create reusable components: auth, api-client, shared-types
- ModeTemplate with Hono backend and SvelteKit frontend
- Auth store refactored to class-based Svelte 5 pattern
- SSR-safe hydrate() pattern for localStorage access
- Frontend builds successfully with Svelte 5 runes

ModeTemplate/frontend/src/routes/+page.svelte

@@ -0,0 +1,17 @@
+<script lang="ts">
+  import { auth } from '$lib/stores/auth.svelte';
+</script>
+
+<h1>Mode Template</h1>
+
+{#if auth.loading}
+  <p>Loading...</p>
+{:else if auth.isAuthenticated}
+  <p>Welcome, {auth.user?.displayName}!</p>
+  <p>Email: {auth.user?.email}</p>
+{:else}
+  <p>Please log in to continue.</p>
+  <button onclick={() => auth.redirectToLogin()}>
+    Sign in with Microsoft
+  </button>
+{/if}