add compile & test worker

src/LiquidCode.Tester.Worker/Services/CallbackService.cs

@@ -0,0 +1,39 @@
+using System.Text;
+using System.Text.Json;
+using LiquidCode.Tester.Common.Models;
+
+namespace LiquidCode.Tester.Worker.Services;
+
+public class CallbackService : ICallbackService
+{
+    private readonly IHttpClientFactory _httpClientFactory;
+    private readonly ILogger<CallbackService> _logger;
+
+    public CallbackService(IHttpClientFactory httpClientFactory, ILogger<CallbackService> logger)
+    {
+        _httpClientFactory = httpClientFactory;
+        _logger = logger;
+    }
+
+    public async Task SendStatusAsync(string callbackUrl, TesterResponseModel response)
+    {
+        _logger.LogInformation("Sending status update to {CallbackUrl} for submit {SubmitId}", callbackUrl, response.SubmitId);
+
+        try
+        {
+            var httpClient = _httpClientFactory.CreateClient();
+            var json = JsonSerializer.Serialize(response);
+            var content = new StringContent(json, Encoding.UTF8, "application/json");
+
+            var httpResponse = await httpClient.PostAsync(callbackUrl, content);
+            httpResponse.EnsureSuccessStatusCode();
+
+            _logger.LogInformation("Status update sent successfully");
+        }
+        catch (Exception ex)
+        {
+            _logger.LogError(ex, "Failed to send status update to {CallbackUrl}", callbackUrl);
+            // Don't throw - callback failures shouldn't stop testing
+        }
+    }
+}