feat: SEO, PWA, and performance optimizations

- Add sitemap.xml endpoint and update robots.txt for SEO - Improve
manifest.json with richer metadata and categories - Add meta tags for
social sharing and accessibility - Preload critical assets and fonts for
faster loading - Optimize login background image and resource hints -
Enhance service worker for better caching strategies - Add security
headers to server responses - Update Vite config for chunking and
dependency optimization - Add logboek.md for project tracking

src/routes/sitemap.xml/+server.ts

@@ -0,0 +1,29 @@
+import type { RequestHandler } from '@sveltejs/kit';
+
+export const GET: RequestHandler = async ({ url }) => {
+	const baseUrl = url.origin;
+	const lastmod = new Date().toISOString().split('T')[0]; // YYYY-MM-DD format
+
+	const sitemap = `<?xml version="1.0" encoding="UTF-8"?>
+<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
+	<url>
+		<loc>${baseUrl}/</loc>
+		<lastmod>${lastmod}</lastmod>
+		<changefreq>weekly</changefreq>
+		<priority>1.0</priority>
+	</url>
+	<url>
+		<loc>${baseUrl}/login</loc>
+		<lastmod>${lastmod}</lastmod>
+		<changefreq>monthly</changefreq>
+		<priority>0.5</priority>
+	</url>
+</urlset>`;
+
+	return new Response(sitemap, {
+		headers: {
+			'Content-Type': 'application/xml',
+			'Cache-Control': 'max-age=86400' // Cache for 24 hours
+		}
+	});
+};