feat(commands): expand standard CAD command coverage

Integrate a large batch of standard CAD commands and fix several
name/behaviour mismatches, with no product references in code.

3D solids (reusing the truck B-rep pipeline):
- SLICE, INTERFERE, PRESSPULL, POLYSOLID, PYRAMID, SECTION
- 3DROTATE, 3DMIRROR, 3DALIGN (cached-solid transforms)

Annotation / text:
- ARCTEXT, SPLINEFIT (Catmull-Rom to Bezier), DIMJOGGED, OBJECTSCALE
  (XData markers honoured by the existing geometry-gen / tessellator)

Blocks / misc:
- NCOPY (block-content extraction via explode_entity)
- OPTIONS, SYNCPVIEWPORTS, THICKEN, plus earlier toggles, aliases,
  system variables, and layer/style/view commands

POINTCLOUD/RECAP and UNDERLAYLAYERS/UOSNAP are intentionally left out:
they require a proprietary binary / PDF-layer parser, a GPU point
renderer, and real test files.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/modules/draw/clipboard/mod.rs

@@ -1,3 +1,4 @@
+pub mod copy_base;
 pub mod copy_clip;
 pub mod cut;
 pub mod paste;