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/PolkadotContext.tsx

@@ -0,0 +1,144 @@
+import React, { createContext, useContext, useEffect, useState, ReactNode } from 'react';
+import { ApiPromise, WsProvider } from '@polkadot/api';
+import { web3Accounts, web3Enable, web3FromAddress } from '@polkadot/extension-dapp';
+import type { InjectedAccountWithMeta } from '@polkadot/extension-inject/types';
+
+interface PolkadotContextType {
+  api: ApiPromise | null;
+  isApiReady: boolean;
+  accounts: InjectedAccountWithMeta[];
+  selectedAccount: InjectedAccountWithMeta | null;
+  setSelectedAccount: (account: InjectedAccountWithMeta | null) => void;
+  connectWallet: () => Promise<void>;
+  disconnectWallet: () => void;
+  error: string | null;
+}
+
+const PolkadotContext = createContext<PolkadotContextType | undefined>(undefined);
+
+interface PolkadotProviderProps {
+  children: ReactNode;
+  endpoint?: string;
+}
+
+export const PolkadotProvider: React.FC<PolkadotProviderProps> = ({
+  children,
+  endpoint = 'wss://beta-rpc.pezkuwi.art' // Beta testnet RPC
+}) => {
+  const [api, setApi] = useState<ApiPromise | null>(null);
+  const [isApiReady, setIsApiReady] = useState(false);
+  const [accounts, setAccounts] = useState<InjectedAccountWithMeta[]>([]);
+  const [selectedAccount, setSelectedAccount] = useState<InjectedAccountWithMeta | null>(null);
+  const [error, setError] = useState<string | null>(null);
+
+  // Initialize Polkadot API
+  useEffect(() => {
+    const initApi = async () => {
+      try {
+        console.log('🔗 Connecting to Pezkuwi node:', endpoint);
+        
+        const provider = new WsProvider(endpoint);
+        const apiInstance = await ApiPromise.create({ provider });
+        
+        await apiInstance.isReady;
+        
+        setApi(apiInstance);
+        setIsApiReady(true);
+        setError(null);
+        
+        console.log('✅ Connected to Pezkuwi node');
+        
+        // Get chain info
+        const [chain, nodeName, nodeVersion] = await Promise.all([
+          apiInstance.rpc.system.chain(),
+          apiInstance.rpc.system.name(),
+          apiInstance.rpc.system.version(),
+        ]);
+        
+        console.log(`📡 Chain: ${chain}`);
+        console.log(`🖥️  Node: ${nodeName} v${nodeVersion}`);
+        
+      } catch (err) {
+        console.error('❌ Failed to connect to node:', err);
+        setError(`Failed to connect to node: ${endpoint}`);
+        setIsApiReady(false);
+      }
+    };
+
+    initApi();
+
+    return () => {
+      if (api) {
+        api.disconnect();
+      }
+    };
+  }, [endpoint]);
+
+  // Connect wallet (Polkadot.js extension)
+  const connectWallet = async () => {
+    try {
+      setError(null);
+      
+      // Enable extension
+      const extensions = await web3Enable('PezkuwiChain');
+      
+      if (extensions.length === 0) {
+        setError('Please install Polkadot.js extension');
+        window.open('https://polkadot.js.org/extension/', '_blank');
+        return;
+      }
+      
+      console.log('✅ Polkadot.js extension enabled');
+      
+      // Get accounts
+      const allAccounts = await web3Accounts();
+      
+      if (allAccounts.length === 0) {
+        setError('No accounts found. Please create an account in Polkadot.js extension');
+        return;
+      }
+      
+      setAccounts(allAccounts);
+      setSelectedAccount(allAccounts[0]); // Auto-select first account
+      
+      console.log(`✅ Found ${allAccounts.length} account(s)`);
+      
+    } catch (err) {
+      console.error('❌ Wallet connection failed:', err);
+      setError('Failed to connect wallet');
+    }
+  };
+
+  // Disconnect wallet
+  const disconnectWallet = () => {
+    setAccounts([]);
+    setSelectedAccount(null);
+    console.log('🔌 Wallet disconnected');
+  };
+
+  const value: PolkadotContextType = {
+    api,
+    isApiReady,
+    accounts,
+    selectedAccount,
+    setSelectedAccount,
+    connectWallet,
+    disconnectWallet,
+    error,
+  };
+
+  return (
+    <PolkadotContext.Provider value={value}>
+      {children}
+    </PolkadotContext.Provider>
+  );
+};
+
+// Hook to use Polkadot context
+export const usePolkadot = (): PolkadotContextType => {
+  const context = useContext(PolkadotContext);
+  if (!context) {
+    throw new Error('usePolkadot must be used within PolkadotProvider');
+  }
+  return context;
+};