Merge PR #436: fix: use _max_tokens_param in max-iterations retry path

Authored by Farukest. Fixes #435. The retry summary in
_handle_max_iterations() hardcoded max_tokens instead of using
_max_tokens_param(), which returns max_completion_tokens for direct
OpenAI API (required by gpt-4o, o-series). The first attempt already
used _max_tokens_param correctly — only the retry path was wrong.
Includes 4 tests for _max_tokens_param provider detection.

run_agent.py

@@ -2743,7 +2743,7 @@ class AIAgent:
                         "messages": api_messages,
                     }
                     if self.max_tokens is not None:
-                        summary_kwargs["max_tokens"] = self.max_tokens
+                        summary_kwargs.update(self._max_tokens_param(self.max_tokens))
                     if summary_extra_body:
                         summary_kwargs["extra_body"] = summary_extra_body