feat(google-gemini): update model YAMLs [bot]

[models-bot]

Auto-generated by poc-agent for provider google-gemini.

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Note

Low Risk
Provider YAML-only changes to model params and metadata; no application or auth logic.

Overview
Updates the Gemini 3.8 live provider metadata so routing and params match Google’s live/thinking variants.

For gemini-3.8-live-extended-thinking, the catalog now exposes a reasoning_effort string param (default medium, allowed low / medium / high), so callers can tune extended-thinking behavior on the realtime extended-thinking model.

For gemini-3.8-live, the YAML adds thinking: true, links an extra official model doc URL, and still removeParams reasoning_effort so the base live model does not advertise that knob.

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