Fix all shadow deprecation warnings across entire mobile app

- Replaced shadowColor/shadowOffset/shadowOpacity/shadowRadius with boxShadow
- Fixed 28 files (21 screens + 7 components)
- Preserved elevation for Android compatibility
- All React Native Web deprecation warnings resolved

Files fixed:
- All screen components
- All reusable components
- Navigation components
- Modal components

shared/blockchain/pezkuwi.ts

@@ -0,0 +1,31 @@
+/**
+ * Pezkuwi/Bizinikiwi blockchain utilities
+ */
+
+import type { BlockchainNetwork } from '../types/blockchain';
+import { getCurrentNetworkConfig } from './endpoints';
+
+/**
+ * Pezkuwi blockchain network configuration
+ * Uses BETA endpoint from centralized endpoints.ts (source of truth)
+ */
+export const PEZKUWI_NETWORK: BlockchainNetwork = {
+  name: 'Pezkuwi',
+  endpoint: getCurrentNetworkConfig().wsEndpoint,
+  chainId: 'pezkuwi',
+};
+
+/**
+ * Default endpoint (reads from environment variables)
+ */
+export const DEFAULT_ENDPOINT = getCurrentNetworkConfig().wsEndpoint;
+
+/**
+ * Get block explorer URL for a transaction
+ * @param txHash - Transaction hash
+ * @returns Block explorer URL
+ */
+export function getExplorerUrl(txHash: string): string {
+  // Update with your actual block explorer URL
+  return `https://explorer.pezkuwichain.app/tx/${txHash}`;
+}