fix: add AuthorizeCall signed extension for PezkuwiChain transactions

PezkuwiChain requires AuthorizeCall as the first signed extension in
all transactions. Without this extension properly configured, transactions
fail with "bad signature" errors.

Added signedExtensions configuration to:
- ApiPromise.create() in Api.tsx
- getApi() in StakingAsync.tsx
- Test API creation functions

This fix enables proper transaction signing for PezkuwiChain mainnet
and teyrchains (Asset Hub, People Chain).

packages/react-hooks/src/ctx/StakingAsync.tsx

@@ -12,9 +12,18 @@ import { useApi } from '@pezkuwi/react-hooks';
 
 const allEndPoints = createWsEndpoints((k, v) => v?.toString() || k);
 
+// PezkuwiChain requires AuthorizeCall signed extension for all transactions
+const PEZKUWI_SIGNED_EXTENSIONS = {
+  AuthorizeCall: {
+    extrinsic: {},
+    payload: {}
+  }
+};
+
 export const getApi = async (url: string[]|string) => {
   const api = await ApiPromise.create({
-    provider: new WsProvider(url)
+    provider: new WsProvider(url),
+    signedExtensions: PEZKUWI_SIGNED_EXTENSIONS
   });
 
   await api.isReadyOrError;