GOOGLE_EFFORTS: tuple[EffortLabel, ...] = ('low', 'medium', 'high')Gemini thinking_level labels.
Applied to every gemini-3* model (the gate in _classify_reasoning_provider),
including Gemini 3 Pro/Flash, 3.1 Pro, and 3.5 Flash — all accept
low/medium/high. minimal is Flash-Lite / original-Pro territory, neither of
which is offered here. See https://ai.google.dev/gemini-api/docs/thinking.