feat: implement skeleton loading across all dynamic sections

Added a shimmering Skeleton component. Integrated loading states for Hero, About (Bento Grid), Reading Log, Projects Archive, and Library pages for a premium UX.

app/components/ui/Skeleton.tsx

@@ -0,0 +1,16 @@
+import { cn } from "@/lib/utils";
+
+export function Skeleton({
+  className,
+  ...props
+}: React.HTMLAttributes<HTMLDivElement>) {
+  return (
+    <div
+      className={cn(
+        "animate-pulse rounded-md bg-stone-200/50 dark:bg-stone-800/50",
+        className
+      )}
+      {...props}
+    />
+  );
+}