fix: only o1-mini does not supports system prompt

Signed-off-by: leo <[email protected]>

Author: love-linger

src/Models/OpenAI.cs

@@ -98,7 +98,7 @@ public void Chat(string prompt, string question, CancellationToken cancellation,
             try
             {
                 var updates = client.CompleteChatStreaming([
-                    ShouldUseDeveloperPrompt() ? new DeveloperChatMessage(prompt) : new SystemChatMessage(prompt),
+                    _model.Equals("o1-mini", StringComparison.Ordinal) ? new UserChatMessage(prompt) : new SystemChatMessage(prompt),
                     new UserChatMessage(question),
                 ], null, cancellation);
 
@@ -115,12 +115,6 @@ public void Chat(string prompt, string question, CancellationToken cancellation,
             }
         }
 
-        private bool ShouldUseDeveloperPrompt()
-        {
-            return _model.Equals("o1", StringComparison.Ordinal) ||
-                _model.Equals("o1-mini", StringComparison.Ordinal);
-        }
-
         private string _name;
         private string _server;
         private string _apiKey;