Repurpose the "Servo Visuale" tab into "Calibrazione Piano". Reuses the
existing WorkPlane + fit_plane_svd infrastructure (moved out of
grasp/visual_servo.py into perception/work_plane.py), extends WorkPlane
with offset_mm, splits fit (preview) from save (commit), and applies a
below-plane + offset filter to every object cloud (sam21_bridge,
_points_via_bbox, _object_cloud_cv bbox branch). Visual-servo feature
removed entirely; the only survivors are the plane bits.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
