- Remove fallback corner estimation (_estimate_corners_from_net) - Gate YOLO detection behind calibration check in detection_loop - Add calibration overlay UI with prominent Calibrate button - Disable Court/Trajectory tabs until system_ready - Skip trajectory/VAR/event polling when uncalibrated - Add system_ready flag to calibration status API Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>