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/.svelte-kit/generated/root.js

@@ -0,0 +1,3 @@
+import { asClassComponent } from 'svelte/legacy';
+import Root from './root.svelte';
+export default asClassComponent(Root);