CTS Building Builder Pro 1.0.13 — Groove End Cleanup

Fixed the missing cleanup after carving groove ends at a wall border.
Removing an end cap can leave its original front-rim edges with no attached
faces. The early cleanup ran while these edges still had an end-cap face,
so they survived and caused the final wall-solid validation to fail.

The selected line/arc/curve engine now uses the established surface-groove
cleanup after opening those ends, restricted to the carved end regions.
Real wall boundary edges and geometry outside those regions are retained.

The line, arc, curve, offset, clipping and component handling from V1.0.12
remain in this build. The final closed-wall validation remains enabled.

Validation includes Ruby syntax, groove math and an executable regression
for the end-rim edge losing its final face. Native SketchUp geometry/UI
execution is not available in the build environment.
