CTS Building Builder Pro v1.0.15

SELECTED-LINE GROOVE EXTENT
- Added Groove Extent with two choices:
  - Selected Portion keeps the exact start and end of the selected line, arc, or connected curve.
  - Extend to Wall Edges continues an open path to the containing wall boundaries.
- The chosen extent updates the SketchUp preview immediately and is included in saved presets.
- Parallel grooves use the same extent as the selected source path.
- Closed curves remain closed and are unaffected by boundary extension.

The V1.0.14 native Push/Pull recess engine and all other Building Builder Pro tools are retained.
