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/app.css

@@ -80,6 +80,7 @@
 		src: url('/fonts/Washington.ttf') format('truetype');
 		font-weight: normal;
 		font-style: normal;
+		font-display: swap;
 	}
 
 	* {
@@ -131,5 +132,30 @@
 	a {
 		color: inherit;
 		text-decoration: none;
+		outline: none;
+		transition: all 0.2s ease;
+	}
+
+	/* Ensure links have visible focus indicators and non-color differentiation */
+	a:hover {
+		text-decoration: underline;
+	}
+
+	a:focus {
+		outline: 2px solid var(--color-ring);
+		outline-offset: 2px;
+		text-decoration: underline;
+	}
+
+	/* Special handling for map attribution links */
+	.maplibregl-ctrl-attrib a {
+		color: #0078a8 !important;
+		text-decoration: underline !important;
+	}
+
+	.maplibregl-ctrl-attrib a:hover,
+	.maplibregl-ctrl-attrib a:focus {
+		text-decoration: underline !important;
+		background-color: rgba(0, 120, 168, 0.1) !important;
 	}
 }