feat: add Phase 1 constraint solver addon, move prior content to GNN/

- Move existing OndselSolver, GNN ML layer, and tooling into GNN/
  directory for integration in later phases
- Add Create addon scaffold: package.xml, Init.py
- Add expression DAG with eval, symbolic diff, simplification
- Add parameter table with fixed/free variable tracking
- Add quaternion rotation as polynomial Expr trees
- Add RigidBody entity (7 DOF: position + unit quaternion)
- Add constraint classes: Coincident, DistancePointPoint, Fixed
- Add Newton-Raphson solver with symbolic Jacobian + numpy lstsq
- Add pre-solve passes: substitution + single-equation
- Add DOF counting via Jacobian SVD rank
- Add KindredSolver IKCSolver bridge for kcsolve integration
- Add 82 unit tests covering all modules

Registers as 'kindred' solver via kcsolve.register_solver() when
loaded by Create's addon_loader.

GNN/OndselSolver/ASMTMotion.cpp

@@ -0,0 +1,52 @@
+/***************************************************************************
+ *   Copyright (c) 2023 Ondsel, Inc.                                       *
+ *                                                                         *
+ *   This file is part of OndselSolver.                                    *
+ *                                                                         *
+ *   See LICENSE file for details about copyright.                         *
+ ***************************************************************************/
+#include <fstream>	
+
+#include "ASMTMotion.h"
+#include "Joint.h"
+
+using namespace MbD;
+
+void ASMTMotion::readMotionSeries(std::vector<std::string>& lines)
+{
+	std::string str = lines[0];
+	std::string substr = "tionSeries";
+	auto pos = str.find(substr);
+	assert(pos != std::string::npos);
+	str.erase(0, pos + substr.length());
+	auto seriesName = readString(str);
+	assert(fullName("") == seriesName);
+	lines.erase(lines.begin());
+	readFXonIs(lines);
+	readFYonIs(lines);
+	readFZonIs(lines);
+	readTXonIs(lines);
+	readTYonIs(lines);
+	readTZonIs(lines);
+}
+
+void ASMTMotion::initMarkers()
+{
+}
+
+void ASMTMotion::storeOnLevel(std::ofstream&, size_t)
+{
+	throw SimulationStoppingError("To be implemented.");
+}
+
+void ASMTMotion::storeOnTimeSeries(std::ofstream&)
+{
+	throw SimulationStoppingError("To be implemented.");
+}
+
+void MbD::ASMTMotion::createMbD(std::shared_ptr<System> mbdSys, std::shared_ptr<Units> mbdUnits)
+{
+	ASMTConstraintSet::createMbD(mbdSys, mbdUnits);
+	auto mbdJt = std::static_pointer_cast<Joint>(mbdObject);
+	mbdSys->addJoint(mbdJt);
+}