port MatrixUtility and SurfaceCurveUtility tests to C++

- include/matrix_utility.hpp: 4x4 mapping matrix R·from=to (Eigen)
- include/projective_math.hpp: dehomogenize, hyperbolicDistance,
  isOnSegment (collinearity + betweenness via 3D cross/dot),
  getPointOnCorrespondingSegment (parameter by arc-length ratio)
- test_matrix_utility.cpp: port of MatrixUtilityTest (1 test)
- test_surface_curve_utility.cpp: port of SurfaceCurveUtilityTest
  testIsBetween and testGetPointOnSegment_SegmentEdge (2 tests)
- tolerance adjusted to 1e-12 for matrix inversion (2.7e-15 rounding
  from Eigen vs jReality's LU; both well within meaningful accuracy)

Total: 16/16 tests pass

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

code/include/matrix_utility.hpp

@@ -0,0 +1,21 @@
+#pragma once
+
+// 4x4 mapping matrix from corresponding point pairs.
+// Ported from de.varylab.discreteconformal.math.MatrixUtility (Java).
+
+#include <Eigen/Dense>
+
+namespace conformallab {
+
+// Find the 4×4 matrix R that maps source points to target points.
+// Each row of `from` / `to` is a homogeneous 4-vector (one point per row).
+// Post-condition: R * from.row(i).T == to.row(i).T for all i.
+//
+// Implementation: R = to^T * (from^T)^{-1}
+// Corresponds to Java MatrixUtility.makeMappingMatrix().
+inline Eigen::Matrix4d makeMappingMatrix(const Eigen::Matrix4d& from,
+                                         const Eigen::Matrix4d& to) {
+    return to.transpose() * from.transpose().inverse();
+}
+
+} // namespace conformallab