Mode switching functionality

src/app-modes/ChallengeMode.js

@@ -0,0 +1,22 @@
+import React from 'react';
+import '../css/App.css';
+import useTelegraph from '../hooks/useTelegraph';
+import ChallengeWord from '../components/ChallengeWord'
+import MorseBufferDisplay from '../components/MorseBufferDisplay'
+
+function ChallengeMode() {
+
+    const {morseCharBuffer} = useTelegraph('challenge')
+    
+    console.log('ChallengeMode.js rendered')
+    
+    return (
+        <>
+            <ChallengeWord word="challenge"/>
+            <MorseBufferDisplay buffer={morseCharBuffer} /><br/>
+        </>
+    );
+
+}
+
+export default React.memo(ChallengeMode);