FEATURE: basic support for GPT-o models (#804)

Caveats

- No streaming, by design
- No tool support (including no XML tools)
- No vision

Open AI will revamt the model and more of these features may
become available.

This solution is a bit hacky for now

lib/completions/dialects/chat_gpt.rb

@@ -39,6 +39,11 @@ module DiscourseAi
           llm_model.max_prompt_tokens - buffer
         end
 
+        # no support for streaming or tools or system messages
+        def is_gpt_o?
+          llm_model.provider == "open_ai" && llm_model.name.include?("o1-")
+        end
+
         private
 
         def tools_dialect
@@ -46,7 +51,11 @@ module DiscourseAi
         end
 
         def system_msg(msg)
-          { role: "system", content: msg[:content] }
+          if is_gpt_o?
+            { role: "user", content: msg[:content] }
+          else
+            { role: "system", content: msg[:content] }
+          end
         end
 
         def model_msg(msg)

lib/completions/endpoints/open_ai.rb

@@ -27,6 +27,17 @@ module DiscourseAi
           AiApiAuditLog::Provider::OpenAI
         end
 
+        def perform_completion!(dialect, user, model_params = {}, feature_name: nil, &blk)
+          if dialect.respond_to?(:is_gpt_o?) && dialect.is_gpt_o? && block_given?
+            # we need to disable streaming and simulate it
+            blk.call "", lambda { |*| }
+            response = super(dialect, user, model_params, feature_name: feature_name, &nil)
+            blk.call response, lambda { |*| }
+          else
+            super
+          end
+        end
+
         private
 
         def model_uri