Handle temperature for gpt-5 models in HTTP client

Updated KoalaHttpClientHandler to also remove the 'temperature' parameter for models starting with 'gpt-5', in addition to those starting with 'o'. This ensures correct request formatting for these model types.

Author: 239573049

src/KoalaWiki/KoalaHttpClientHander.cs

@@ -30,7 +30,7 @@ protected override async Task<HttpResponseMessage> SendAsync(
         }
 
         // GPT o系列不能传递温度
-        if (model.StartsWith("o"))
+        if (model.StartsWith("o") || model.StartsWith("gpt-5"))
         {
             json.Remove("temperature");
         }