feat(webapp): add installable PWA support

WebApp/src/routes/+layout.svelte

@@ -1,15 +1,41 @@
 <script lang="ts">
+	// @ts-nocheck
 	import '../app.css';
 	import { onMount } from 'svelte';
+	import { registerSW } from 'virtual:pwa-register';
 	import favicon from '$lib/assets/favicon.svg';
 	import { appController } from '$lib/app/controller';
+	import { clearInstallPrompt, setInstallPrompt, setOfflineReady, setUpdateAvailable } from '$lib/pwa';
 
 	let { children } = $props();
 
 	onMount(() => {
+		registerSW({
+			onNeedRefresh() {
+				setUpdateAvailable(true);
+			},
+			onOfflineReady() {
+				setOfflineReady(true);
+			}
+		});
+
+		const handleBeforeInstallPrompt = (event) => {
+			event.preventDefault();
+			setInstallPrompt(event);
+		};
+
+		const handleAppInstalled = () => {
+			clearInstallPrompt();
+		};
+
+		window.addEventListener('beforeinstallprompt', handleBeforeInstallPrompt);
+		window.addEventListener('appinstalled', handleAppInstalled);
+
 		void appController.init();
 
 		return () => {
+			window.removeEventListener('beforeinstallprompt', handleBeforeInstallPrompt);
+			window.removeEventListener('appinstalled', handleAppInstalled);
 			void appController.destroy();
 		};
 	});