fix: SEO canonical URLs, LCP performance, remove unused dependencies

- Remove duplicate app/projects/ route (was causing 5xx and soft 404)
- Fix nginx: redirect www.dk0.dev → dk0.dev (non-www canonical)
- Fix not-found.tsx: locale-prefixed links, remove framer-motion dependency
- Add fetchPriority='high' and will-change to Hero LCP image
- Add preconnect hints for hardcover.app and cms.dk0.dev
- Reduce background blur from 100px to 80px (LCP rendering delay)
- Remove boneyard-js (~20 KiB), replace with custom Skeleton component
- Remove react-icons (~10 KiB), replace with inline SVGs
- Conditionally render mobile menu (saves ~20 DOM nodes)
- Add /books to sitemap
- Optimize image config with explicit deviceSizes/imageSizes

lib/sitemap.ts

@@ -36,15 +36,15 @@ export async function getSitemapEntries(): Promise<SitemapEntry[]> {
   const baseUrl = getBaseUrl();
   const nowIso = new Date().toISOString();
 
-  const staticPaths = ["", "/projects", "/legal-notice", "/privacy-policy"];
+  const staticPaths = ["", "/projects", "/books", "/legal-notice", "/privacy-policy"];
   const staticEntries: SitemapEntry[] = locales.flatMap((locale) =>
     staticPaths.map((p) => {
       const path = p === "" ? `/${locale}` : `/${locale}${p}`;
       return {
         url: `${baseUrl}${path}`,
         lastModified: nowIso,
-        changefreq: p === "" ? "weekly" : p === "/projects" ? "weekly" : "yearly",
-        priority: p === "" ? 1.0 : p === "/projects" ? 0.8 : 0.5,
+changefreq: p === "" ? "weekly" : (p === "/projects" || p === "/books") ? "weekly" : "yearly",
+            priority: p === "" ? 1.0 : (p === "/projects" || p === "/books") ? 0.8 : 0.5,
       };
     }),
   );