Grade any physical Pokémon, Magic: The Gathering, Yu-Gi-Oh, or Digimon trading card using a 3-stage AI pipeline: (1) Qwen Vision LLM analyzes corners, edges, and surface defects, (2) OpenCV measures exact centering ratios programmatically, (3) BGS professional capping algorithm adjusts the final grade. Returns PSA/Beckett-calibrated subgrades and an overall condition score. Accepts card image URLs or base64.