Optional: snap world-space points to the active grid (or any other
snap target). Applied to both the center (on onStart) and the
current cursor (on onMove), so the live overlay's radius/rotation
is computed from snapped points instead of raw cursor positions.
When omitted, behavior is identical to today (identity passthrough).
Optional: snap world-space points to the active grid (or any other snap target). Applied to both the center (on
onStart) and the current cursor (ononMove), so the live overlay's radius/rotation is computed from snapped points instead of raw cursor positions. When omitted, behavior is identical to today (identity passthrough).