get udp example working

backend/Program.cs

@@ -1,12 +1,52 @@
 using System;
+using System.Net;
+using System.Net.Sockets;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
 
 namespace Love2DBackend
 {
     class Program
     {
-        static void Main(string[] args)
+        static async Task Main(string[] args)
         {
-            Console.WriteLine("Hello from LÖVE2D Backend!");
+            Console.WriteLine("LÖVE2D Backend - UDP Server");
+            Console.WriteLine("Starting server on port 7777...");
+
+            using (var udpServer = new UdpClient(7777))
+            {
+                Console.WriteLine("Server listening on 0.0.0.0:7777");
+
+                var cts = new CancellationTokenSource();
+
+                // Handle Ctrl+C gracefully
+                Console.CancelKeyPress += (s, e) =>
+                {
+                    e.Cancel = true;
+                    cts.Cancel();
+                };
+
+                try
+                {
+                    while (!cts.Token.IsCancellationRequested)
+                    {
+                        var result = await udpServer.ReceiveAsync(cts.Token);
+                        var message = Encoding.UTF8.GetString(result.Buffer);
+                        var clientEndpoint = result.RemoteEndPoint;
+
+                        Console.WriteLine($"[{clientEndpoint}] {message}");
+
+                        // Echo back
+                        var response = Encoding.UTF8.GetBytes($"Echo: {message}");
+                        await udpServer.SendAsync(response, response.Length, clientEndpoint);
+                    }
+                }
+                catch (OperationCanceledException)
+                {
+                    Console.WriteLine("Server stopped.");
+                }
+            }
         }
     }
 }