Add method to send progress updates to caller

Introduced a `SendProgressUpdate` method in `WeatherUpdateHub` to allow sending progress messages specifically to the calling client. This enhances client feedback during operations.

Api/SignalR/WeatherUpdateHub.cs

@@ -10,5 +10,11 @@ namespace Api.SignalR
             // Broadcast the message to all connected clients.
             await Clients.All.SendAsync("ReceiveMessage", user, message);
         }
+        
+        public async Task SendProgressUpdate(string message)
+        {
+            // Send a message to the caller.
+            await Clients.Caller.SendAsync("ProgressUpdate", message);
+        }
     }
 }