Groq's OpenAI-compatible wire accepts top-level reasoning_effort only as
"none" or "default" (#75089, Defect 1); the custom profile forwarded the
configured graded level ("medium"/"high") and the request still 400'd on
both the main transport and the auxiliary path. The clamp lives in
CustomProfile.build_api_kwargs_extras, keyed on the resolved base_url host,
so both paths share it. The aux bare-key case now drives call_llm with a
fake client instead of the private _build_call_kwargs.
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