- Add missing (#423) reference to the CHANGELOG entry.
- Restore regression coverage for gemini-2.5-flash thinking-budget
alongside gemini-3.5-flash via a shared test helper.
Google will also discontinue gemini-2.5-flash-lite on October 20, 2026.
The thinking-budget guard already covers the 3.5 Flash-Lite model via
substring matching. Verified gemini-3.5-flash-lite against the live API.
Google will discontinue gemini-2.5-flash on October 20, 2026.
Update the default model for the gemini provider to gemini-3.5-flash
and keep the thinking-budget workaround for both the legacy model and
the new default. Update docs and smoke-test defaults accordingly.
Tested against the live Gemini API in a Docker container.