Implement SignalR integration and refactor WeatherPage

Added SignalR for real-time progress updates during weather data fetch. Refactored WeatherPage to use a new reusable WeatherGrid component and SignalRHelper. Improved loading UI with a radial progress indicator.

Api/Program.cs

@@ -15,9 +15,10 @@ builder.Services.AddCors(options =>
 {
     options.AddDefaultPolicy(policy =>
     {
-        policy.AllowAnyOrigin()
+        policy.WithOrigins("http://localhost:5173")
             .AllowAnyHeader()
-            .AllowAnyMethod();
+            .AllowAnyMethod()
+            .AllowCredentials();
     });
 });
 
@@ -41,6 +42,14 @@ var summaries = new[]
 
 app.MapGet("/weatherforecast", async () =>
     {
+        var hub = app.Services.GetRequiredService<IHubContext<WeatherUpdateHub>>();
+        for (var i = 0; i < 100; i++)
+        {
+            await hub.Clients.All.SendAsync("ProgressUpdate", "None", $$"""{"percentage": "{{i}}", "message": "{{DateTime.Now.Millisecond}}"}""");
+            await Task.Delay(100);
+        }
+
+
         var forecast = Enumerable.Range(1, 2500).Select(index =>
                 new WeatherForecast
                 (