feat: Initialize Turtle Control Center with React and WebSocket server

- Added index.html for the main entry point of the client application.
- Created package.json for client dependencies and scripts.
- Implemented App component with view controls and layout.
- Added CSS styles for the application and components.
- Developed ControlPanel component for turtle management and commands.
- Created Map3D component for 3D visualization of turtles.
- Established Zustand store for state management of turtles and WebSocket connection.
- Set up server with Express and WebSocket for handling turtle updates and commands.
- Added REST API endpoints for turtle status updates and command handling.
- Implemented start.sh script for setting up and running the application.

client/src/App.jsx

@@ -0,0 +1,54 @@
+import React, { useEffect, useState } from 'react';
+import Map3D from './components/Map3D';
+import ControlPanel from './components/ControlPanel';
+import { useTurtleStore } from './store/turtleStore';
+import './App.css';
+
+function App() {
+  const connect = useTurtleStore((state) => state.connect);
+  const [view, setView] = useState('split'); // 'split', 'map', 'panel'
+
+  useEffect(() => {
+    connect();
+  }, [connect]);
+
+  return (
+    <div className="app">
+      <div className="view-controls">
+        <button 
+          className={view === 'split' ? 'active' : ''}
+          onClick={() => setView('split')}
+        >
+          📊 Split View
+        </button>
+        <button 
+          className={view === 'map' ? 'active' : ''}
+          onClick={() => setView('map')}
+        >
+          🗺️ Map Only
+        </button>
+        <button 
+          className={view === 'panel' ? 'active' : ''}
+          onClick={() => setView('panel')}
+        >
+          🎮 Control Only
+        </button>
+      </div>
+
+      <div className={`app-content ${view}`}>
+        {(view === 'split' || view === 'map') && (
+          <div className="map-container">
+            <Map3D />
+          </div>
+        )}
+        {(view === 'split' || view === 'panel') && (
+          <div className="panel-container">
+            <ControlPanel />
+          </div>
+        )}
+      </div>
+    </div>
+  );
+}
+
+export default App;