New Features

• GeoGebra XML static validator: automatically checks whether AI-generated plots are well-formed (command spelling, tag closure, object naming, etc.).
• Self-repair loop: validation errors are fed back to the model to continue and correct, replacing weak retries and reducing "half-finished figures".
• Visible front-end error hints: when GeoGebra rendering fails, a Chinese error bar is shown for easier diagnosis.
• Stepwise plotting foundation: semantic retrieval integrated (references similar figures' methods while plotting), and billing is converted by token.
• Evaluation framework: built a 45-question eval set and a headless-browser ground-truth scorer for offline plotting-quality measurement.