wallet provider fix

app/src/app/WalletProviders.tsx

@@ -21,8 +21,13 @@ export const NetworkContext = React.createContext<NetworkContextValue>({
 export function WalletProviders({ children }: { children: React.ReactNode }) {
   const [network, setNetwork] = useState<WalletAdapterNetwork>(WalletAdapterNetwork.Devnet)
 
-  // You can also provide a custom RPC endpoint
-  const endpoint = useMemo(() => clusterApiUrl(network), [network]);
+  const endpoint = useMemo(
+    () =>
+      (network as string) === 'localnet'
+        ? 'http://localhost:8899'
+        : clusterApiUrl(network),
+    [network],
+  );
 
   const onError = useCallback((error: WalletError) => {
     console.warn('[wallet]', error.name, error.message, error.error)