Generate AND edit images using Google Nano Banana 2 (Gemini 3.1 Flash Image) via OpenRouter. TRIGGER when the user asks to generate, create, make, draw, render, produce, edit, restyle, modify, retouch, alter, change, enhance, combine, or remix any image, photo, picture, illustration, render, artwork, logo, icon, or visual. Also triggers on phrases like "give me a picture of", "make me an image", "generate a photo", "render this", "draw me", "edit this image", "change the background of", "make this look like", "combine these images", "flicky". Supports text-to-image, image editing with reference images, multi-image composition, parallel variations, and auto-opens results in Preview. Reads OPENROUTER_API_KEY from environment.