chore: finalize migration cleanup

- Remove dev-dist/registerSW.js (no longer needed without vite-pwa plugin)
- Fix import order in layout.svelte
- Complete migration to native SvelteKit PWA

dev-dist/registerSW.js

@@ -1 +0,0 @@
-if('serviceWorker' in navigator) navigator.serviceWorker.register('/dev-sw.js?dev-sw', { scope: '/', type: 'classic' })

src/routes/+layout.svelte

@@ -1,6 +1,6 @@
 <script lang="ts">
-	import './layout.css';
 	import favicon from '$lib/assets/favicon.svg';
+	import './layout.css';
 	
 	let { children } = $props();
 </script>