Use IHttpClientFactory instead of singleton HttpClient in WeatherTool

Replace AddSingleton<HttpClient>() with AddHttpClient() in DI registration,
and inject IHttpClientFactory into WeatherTool so each request gets a
properly managed HttpClient instance with correct handler lifecycle.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: mattleibow

10.0/AI/LocalChatClientWithTools/src/MauiProgram.cs

@@ -27,7 +27,7 @@ public static MauiApp CreateMauiApp()
 		builder.Services.AddSingleton<MainPage>();
 
         // Register tool services
-        builder.Services.AddSingleton<HttpClient>();
+        builder.Services.AddHttpClient();
         builder.Services.AddSingleton<CalculatorTool>();
         builder.Services.AddSingleton<WeatherTool>();
         builder.Services.AddSingleton<FileOperationsTool>();

10.0/AI/LocalChatClientWithTools/src/Services/Tools/WeatherTool.cs

@@ -5,7 +5,7 @@
 
 namespace LocalChatClientWithTools.Services.Tools;
 
-public partial class WeatherTool(HttpClient httpClient)
+public partial class WeatherTool(IHttpClientFactory httpClientFactory)
 {
     public static AIFunction CreateAIFunction(IServiceProvider services)
         => AIFunctionFactory.Create(
@@ -24,6 +24,8 @@ public async Task<WeatherResult> GetWeatherAsync(
 
         try
         {
+            using var httpClient = httpClientFactory.CreateClient();
+
             var geoUrl = $"https://geocoding-api.open-meteo.com/v1/search?name={Uri.EscapeDataString(location)}&count=1";
             using var geoResponse = await httpClient.GetAsync(geoUrl, cancellationToken);
             geoResponse.EnsureSuccessStatusCode();