Reorganize repository into monorepo structure

Restructured the project to support multiple frontend applications:
- Move web app to web/ directory
- Create pezkuwi-sdk-ui/ for Polkadot SDK clone (planned)
- Create mobile/ directory for mobile app development
- Add shared/ directory with common utilities, types, and blockchain code
- Update README.md with comprehensive documentation
- Remove obsolete DKSweb/ directory

This monorepo structure enables better code sharing and organized
development across web, mobile, and SDK UI projects.

web/src/components/ui/skeleton.tsx

@@ -0,0 +1,25 @@
+import * as React from "react"
+import { cn } from "@/lib/utils"
+
+interface SkeletonProps extends React.HTMLAttributes<HTMLDivElement> {
+  animated?: boolean
+}
+
+function Skeleton({
+  className,
+  animated = true,
+  ...props
+}: SkeletonProps) {
+  return (
+    <div
+      className={cn(
+        "rounded-md bg-muted/70",
+        animated && "animate-pulse",
+        className
+      )}
+      {...props}
+    />
+  )
+}
+
+export { Skeleton }