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/index.ts

@@ -5,6 +5,6 @@
  * that can be used across web and mobile applications.
  */
 
-export * from './polkadot';
+export * from './pezkuwi';
 
 // Add more blockchain utility exports as needed

shared/blockchain/pezkuwi.ts

@@ -1,5 +1,5 @@
 /**
- * Polkadot/Substrate blockchain utilities
+ * Pezkuwi/Bizinikiwi blockchain utilities
  */
 
 import type { BlockchainNetwork } from '../types/blockchain';