Add a direct Google Gemini provider (opt-in via config)

[isene]

Adds a second image/vision provider so the daemon can talk straight to Google's Gemini API (AI Studio generateContent) instead of going through OpenRouter.

What

• New config key: [imagegen] provider = "gemini" | "openrouter".
• Default is openrouter — existing configs and behavior are unchanged.
• With provider = "gemini", api_key is a Google AI Studio key and requests go to generativelanguage.googleapis.com/.../generateContent; both the illustration and the handwriting-Q&A paths are handled.

Why

Lets people who already have (or would rather use) a Google AI Studio key skip the OpenRouter account and middleman. Same underlying Gemini image models.

How

imagegen.rs grows a small Provider enum; the client builds either the OpenRouter chat-completions request or the Gemini generateContent request and parses each response shape. main.rs parses the new provider key; the default keeps OpenRouter.

Built and running on a real reMarkable 2. Kept the change self-contained and opt-in so it's easy to take or leave. Thanks for inkling — it's a lovely project.

🤖 Generated with Claude Code