Three issues found in activity logs:
1. Image model IDs stale — FLUX and Seedream removed from OpenRouter.
Updated to current models: Gemini 2.5/3.1 Flash Image, Gemini 3 Pro
Image, GPT-5 Image/Mini. Default changed to gemini-2.5-flash-image.
2. openrouter/free router wraps upstream 429 errors in HTTP 200 body
with error object. Both text and image response parsers now detect
this pattern and surface a proper RuntimeException.
3. Image request used modalities: ["image"] but Gemini needs
["image", "text"]. Updated to include both.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>