CV Calibrate Camera (ChArUco)

Camera intrinsics + lens distortion from a batch of ChArUco board photos - the robust alternative to 'CV Calibrate Camera (Chessboard)'. A plain chessboard view is thrown away unless EVERY inner corner is visible; a ChArUco view contributes whatever corners it can identify, so photos where the board runs off the frame or is partly occluded still count. That means fewer, easier shots for the same coverage - and coverage of the image CORNERS, which is exactly where distortion is estimated, is what a full-board requirement makes hardest. Views with too few corners are skipped. Failure-tolerant: fewer than 3 usable views returns found=false with an identity matrix and zero distortion.