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/contexts/AppContext.tsx

@@ -0,0 +1,36 @@
+import React, { createContext, useContext, useState, useEffect } from 'react';
+import { v4 as uuidv4 } from 'uuid';
+import { toast } from '@/components/ui/use-toast';
+
+interface AppContextType {
+  sidebarOpen: boolean;
+  toggleSidebar: () => void;
+}
+
+const defaultAppContext: AppContextType = {
+  sidebarOpen: false,
+  toggleSidebar: () => {},
+};
+
+const AppContext = createContext<AppContextType>(defaultAppContext);
+
+export const useAppContext = () => useContext(AppContext);
+
+export const AppProvider: React.FC<{ children: React.ReactNode }> = ({ children }) => {
+  const [sidebarOpen, setSidebarOpen] = useState(false);
+
+  const toggleSidebar = () => {
+    setSidebarOpen(prev => !prev);
+  };
+
+  return (
+    <AppContext.Provider
+      value={{
+        sidebarOpen,
+        toggleSidebar,
+      }}
+    >
+      {children}
+    </AppContext.Provider>
+  );
+};