- new photo-ai service: FastAPI + Real-ESRGAN x2plus on CPU, internal only - async job queue in server (POST enhance-ai / GET status), 5min timeout, sequential processing - keep original photo backup (entries.photo_original_path, uploads/.originals), restore-original endpoint - UI: AI button and restore-original button in enhance modal - db: photo_original_path column (init.sql, migration.sql, runtime ensure)