CTS Building Builder Pro 1.0.12 — Selected-Line / Curve Groove Test Build

The selected-guide workflow now uses one direct ribbon-recess engine for
straight lines, polylines, arcs and closed curves. It does not invoke Solid
Tools subtract, split or Follow Me.

- Non-solid and standalone wall faces are accepted as well as grouped walls.
- Loose guides detect the wall surface beneath them.
- Picking a curve selects all its tessellation segments.
- Ribbon boundaries are clipped to the original wall outline and openings.
- Recess floors and side surfaces are built in the original wall context.
- Shared bottom vertices are mitered across selected wall facets.
- Actual host geometry determines inward direction and available thickness.
- Component copies are made unique inside the groove undo transaction.
- Failed splitting, depth, floor or solid checks abort the complete operation.
- Original surface-based groove properties and other tools are retained.

Validation: Ruby 3.3 syntax, numeric geometry regressions and RBZ integrity.
SketchUp's native face-splitting/geometry kernel was not available in the
build environment. Test this build on a copy of the affected model first.
