Default both build scripts to orcacad-deps, not the other fork's image

Both scripts defaulted IMAGE to snaporca-deps. That image is Snapmaker-based
and lacks Eigen 5.0.1, CGAL 5.6.3, wx 3.3.2 and Python 3.12 Development.Embed,
so running either script here without an explicit IMAGE= dies at CMake
configure — which is a large part of why this fork reached M8 having never once
compiled (1633005bba). The volume defaults were fixed in that commit; the image
default was missed in both files.

docker-iter-build.sh also never mounted deps_src, so it could not have
configured even with the right image: root CMakeLists.txt:947 FATAL_ERRORs
when deps_src/pybind11/include/pybind11/pybind11.h is absent, and
src/CMakeLists.txt pulls semver/hints/imgui/imguizmo/hidapi from the same tree.
kernel-test.sh got that mount in 1633005bba; this is the same fix for the GUI
build path, needed before the Phase B GUI work can be ported here.

CadDocument.hpp: mate_kind comment, mirrored verbatim from snaporca dbaa104f62
so the header stays byte-identical across forks.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

src/libslic3r/CadDocument.hpp

@@ -296,7 +296,13 @@ struct CadFeature {
     double rib_depth{10};       // extrude distance along the sketch-plane normal (mm)
 
     // --- Mate (assembly) ---
-    int    mate_kind{0};        // 0 = Fastened, 1 = Planar (M8b adds 2/3/4)
+    // 0 Fastened   — all 6 DOF fixed: B's frame is driven onto A's exactly.
+    // 1 Planar     — z axes aligned, normal distance set to mate_offset; in-plane position free.
+    // 2 Revolute   — axes collinear, position on the axis fixed; rotation about z free.
+    // 3 Slider     — orientation fully fixed, perpendicular position fixed; axial slide free.
+    // 4 Cylindrical— axes collinear, perpendicular fixed; both spin and axial slide free.
+    // A "free" DOF is preserved from the body's current placement, not zeroed.
+    int    mate_kind{0};
     int    mate_cs_a{-1};       // feature index of the FIXED CoordSys (mate connector A)
     int    mate_cs_b{-1};       // feature index of the CoordSys on the body that MOVES
     double mate_offset{0};      // translation along A's z, mm