feat: support gemini

[programming-with-ia]

opening this issue to get notified when gemini support is added.
it would be great to use google gemini models.
thanks.

[samyogdhital]

waiting for supporting gemini harness.

[rommyarb]

What could be the challenge of implementing Gemini support to t3code?

[TzuChin]

waiting for supporting gemini

[jorgeluiso]

+1 for Having a Gemini Harness. Gemini is the only sub missing a desktop app.

• Anthropic Subscription -> Claude Desktop
• Open AI Subscription -> Codex
• Google AI Subscription -> Missing

T3 - Code could be my primary to use my sub token allocation for Gemini.

[Marve10s]

Gemini CLI support is implemented in #1983 — currently open for review. The PR adds Gemini as a first-class provider: sessions, model picker, thinking controls for Gemini 2.5 / 3, git text generation, and UI integration. Feedback and testing welcome.