refactor WebSocket and fetch API URLs to use environment variables for better configuration

Frontend/.env.example

@@ -0,0 +1,7 @@
+# Monaco Frontend Environment Variables
+
+# Backend API URL (Monaco code execution server)
+VITE_API_URL=http://localhost:8080
+
+# Faculty API URL (Faculty/Student management backend)
+VITE_FACULTY_API_URL=http://localhost:5000/api

Frontend/src/components/CodeChallenge.jsx

@@ -339,7 +339,10 @@ int main() {
     }
 
     console.log('Creating new WebSocket connection');
-    const wsUrl = `ws://localhost:8080/api/ws/terminal/${id}`;
+    const apiUrl = import.meta.env.VITE_API_URL || 'http://localhost:8080';
+    const wsProtocol = window.location.protocol === 'https:' ? 'wss:' : 'ws:';
+    const wsBaseUrl = apiUrl.replace(/^https?:\/\//, '');
+    const wsUrl = `${wsProtocol}//${wsBaseUrl}/api/ws/terminal/${id}`;
     const socket = new WebSocket(wsUrl);
     
     socket.onopen = () => {
@@ -515,7 +518,8 @@ int main() {
       
       try {
         // Submit code to the backend
-        const response = await fetch('http://localhost:8080/api/submit', {
+        const apiUrl = import.meta.env.VITE_API_URL || 'http://localhost:8080';
+        const response = await fetch(`${apiUrl}/api/submit`, {
           method: 'POST',
           headers: {
             'Content-Type': 'application/json',