feat: improve accessibility and SEO (100/100 Lighthouse score)

Fixes color contrast, canonical URLs, viewport scaling, semantic lists,

and resolves 404 errors for manifest/imgproxy.

middleware.ts

@@ -21,7 +21,8 @@ export default function middleware(request: NextRequest) {
     pathname.startsWith('/health') ||
     pathname.includes('/api/og') ||
     pathname.includes('opengraph-image') ||
-    pathname.endsWith('sitemap.xml')
+    pathname.endsWith('sitemap.xml') ||
+    pathname.endsWith('manifest.webmanifest')
   ) {
     return NextResponse.next();
   }
@@ -94,6 +95,6 @@ export default function middleware(request: NextRequest) {
 
 export const config = {
   matcher: [
-    '/((?!api|_next/static|_next/image|favicon.ico|.*\\.(?:svg|png|jpg|jpeg|gif|webp|pdf|txt|vcf|xml)$).*)',
+    '/((?!api|_next/static|_next/image|favicon.ico|manifest.webmanifest|.*\\.(?:svg|png|jpg|jpeg|gif|webp|pdf|txt|vcf|xml)$).*)',
   ],
 };