fix(chat_completions): broaden tool_name strip docstring + AUTHOR_MAP

Salvage follow-up to PR #28958 (savanne-kham):

- convert_messages() docstring now explicitly documents the tool_name strip
  alongside Codex fields, names which providers reject it (Fireworks,
  Moonshot/Kimi), and why permissive providers (OpenRouter, MiniMax)
  masked the bug.
- AUTHOR_MAP entry for savanne.kham@protonmail.com -> savanne-kham.

agent/transports/chat_completions.py

@@ -112,11 +112,21 @@ class ChatCompletionsTransport(ProviderTransport):
     def convert_messages(
         self, messages: list[dict[str, Any]], **kwargs
     ) -> list[dict[str, Any]]:
-        """Messages are already in OpenAI format — sanitize Codex leaks only.
+        """Messages are already in OpenAI format — strip internal fields
+        that strict chat-completions providers reject with HTTP 400/422.
 
-        Strips Codex Responses API fields (``codex_reasoning_items`` /
-        ``codex_message_items`` on the message, ``call_id``/``response_item_id``
-        on tool_calls) that strict chat-completions providers reject with 400/422.
+        Strips:
+
+        - Codex Responses API fields: ``codex_reasoning_items`` /
+          ``codex_message_items`` on the message, ``call_id`` /
+          ``response_item_id`` on ``tool_calls`` entries.
+        - ``tool_name`` on tool-result messages — written by
+          ``make_tool_result_message()`` for the SQLite FTS index, but not
+          part of the Chat Completions schema. Strict providers (Fireworks,
+          Moonshot/Kimi) reject any payload containing it with
+          ``Extra inputs are not permitted, field: 'messages[N].tool_name'``.
+          Permissive providers (OpenRouter, MiniMax) silently ignore the
+          field, which masked the bug for months.
         """
         needs_sanitize = False
         for msg in messages: