Integrate live blockchain data for delegation features

- Created useDelegation hook to fetch real delegation data from blockchain
  - Queries democracy.voting pallet for all delegations
  - Tracks delegate totals, delegator counts, and voting power
  - Calculates delegate performance metrics and success rates
  - Fetches user's own delegations with conviction levels
  - Auto-refreshes every 30 seconds for live updates
  - Provides delegateVotes and undelegateVotes transaction builders

- Updated DelegationManager component to use live data
  - Replaced mock delegates with real blockchain delegates
  - Replaced mock delegations with user's actual delegations
  - Added loading states with spinner during data fetch
  - Added error handling with user-friendly messages
  - Added "Live Blockchain Data" badge for transparency
  - Formatted token amounts from blockchain units (12 decimals)
  - Show delegate addresses in monospace font
  - Display delegator count and conviction levels
  - Empty states for no delegates/delegations scenarios

- Enhanced PolkadotContext with isConnected property
  - Added isConnected as alias for isApiReady
  - Maintains backward compatibility with existing hooks

- Added formatNumber utility to lib/utils
  - Formats large numbers with K/M/B suffixes
  - Handles decimals and edge cases
  - Consistent formatting across all components

All delegation data now comes from live blockchain queries.

web/src/contexts/PolkadotContext.tsx

@@ -6,6 +6,7 @@ import type { InjectedAccountWithMeta } from '@polkadot/extension-inject/types';
 interface PolkadotContextType {
   api: ApiPromise | null;
   isApiReady: boolean;
+  isConnected: boolean;
   accounts: InjectedAccountWithMeta[];
   selectedAccount: InjectedAccountWithMeta | null;
   setSelectedAccount: (account: InjectedAccountWithMeta | null) => void;
@@ -119,6 +120,7 @@ export const PolkadotProvider: React.FC<PolkadotProviderProps> = ({
   const value: PolkadotContextType = {
     api,
     isApiReady,
+    isConnected: isApiReady, // Alias for backward compatibility
     accounts,
     selectedAccount,
     setSelectedAccount,