Moved from axios to Fetch API, Added user object to the AuthState

frontend/app/(app)/index.js

@@ -3,11 +3,13 @@ import { Text, View } from "react-native";
 import { useAuth } from "../context/AuthContext";
 
 export default function Index() {
-  const { onLogout } = useAuth();
-  const user = "debil"
+  const { onLogout, authState } = useAuth();
+
+  const user = authState.user;
+
   return (
     <View style={{ flex: 1, justifyContent: "center", alignItems: "center" }}>
-      <Text>Welcome {user}</Text>
+      <Text>Welcome {user.username}</Text>
       <Text
         onPress={() => {
           // The `app/(app)/_layout.tsx` will redirect to the sign-in screen.