Add crash-resume + GDrive sync to identifier-continue training

Phase 6: VMMRdb identifier extension (196 → up to ~9,170 make/model/year)

XGBoost(C): mask-area cost feature from the YOLOv8-seg model

Add Stanford Cars as 'no damage' negatives for the classifier

checkpoint-3: comparison report, FastAPI, Gradio, HF Space deploy

Initial commit: end-to-end car damage + repair-cost predictor