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

app/components/ShaderGradientBackground.tsx

@@ -5,54 +5,27 @@ export default function ShaderGradientBackground() {
   return (
     <div
       aria-hidden="true"
-      style={{
-        position: "fixed",
-        inset: 0,
-        zIndex: -1,
-        overflow: "hidden",
-        pointerEvents: "none",
-      }}
+      className="fixed inset-0 -z-10 overflow-hidden pointer-events-none"
     >
-      {/* Upper-left: crimson → pink (was Sphere 1: posX=-2.5, posY=1.5) */}
       <div
+        className="absolute -top-[10%] -left-[15%] w-[55%] h-[65%] rounded-full opacity-60"
         style={{
-          position: "absolute",
-          top: "-10%",
-          left: "-15%",
-          width: "55%",
-          height: "65%",
-          background:
-            "radial-gradient(ellipse at 50% 50%, #b01040 0%, #e167c5 40%, transparent 70%)",
-          filter: "blur(100px)",
-          opacity: 0.6,
+          background: "radial-gradient(ellipse at 50% 50%, #b01040 0%, #e167c5 40%, transparent 70%)",
+          filter: "blur(80px)",
         }}
       />
-      {/* Right-center: pink → crimson (was Sphere 2: posX=2.0, posY=-0.5) */}
       <div
+        className="absolute top-[25%] -right-[10%] w-[50%] h-[60%] rounded-full opacity-55"
         style={{
-          position: "absolute",
-          top: "25%",
-          right: "-10%",
-          width: "50%",
-          height: "60%",
-          background:
-            "radial-gradient(ellipse at 50% 50%, #e167c5 0%, #b01040 40%, transparent 70%)",
-          filter: "blur(100px)",
-          opacity: 0.55,
+          background: "radial-gradient(ellipse at 50% 50%, #e167c5 0%, #b01040 40%, transparent 70%)",
+          filter: "blur(80px)",
         }}
       />
-      {/* Lower-left: orange → pink (was Sphere 3: posX=-0.5, posY=-2.0) */}
       <div
+        className="absolute -bottom-[15%] left-[5%] w-[50%] h-[60%] rounded-full opacity-50"
         style={{
-          position: "absolute",
-          bottom: "-15%",
-          left: "5%",
-          width: "50%",
-          height: "60%",
-          background:
-            "radial-gradient(ellipse at 50% 50%, #b04a17 0%, #e167c5 40%, transparent 70%)",
-          filter: "blur(100px)",
-          opacity: 0.5,
+          background: "radial-gradient(ellipse at 50% 50%, #b04a17 0%, #e167c5 40%, transparent 70%)",
+          filter: "blur(80px)",
         }}
       />
     </div>