project() creates broken/unusable Compound when called on a Solid

Hi,

the project function silently generates an unusable Compound when trying to project(some_solid).. When calling .faces(), .edges() or .vertices() on that Compound (or trying to show() it), an exception is raised.

That project does not work on a Solid is not the issue and is expected according to the documentation, which states: _"Parameters: objects (Union[Edge, Face, Wire, VectorLike, Vertex] or Iterable of) – objects or points to project"_

However, the behavior of the function should be more clear. I would expect a clear message like ValueError("project does not accept solids, try your_solid.faces()"), but not a broken object.

Steps to reproduce

from build123d import *
foo = project(extrude(Rectangle(20,20), 3), Plane.XY)
print(foo) # it's a Compound
foo.vertices()

Expected behaviour

The foo = project(...) line should throw a ValueError with a helpful error message

or: The foo = project(some_solid) call should behave the same as foo = project(some_solid.faces()).

Actual behavior

The foo.vertices() call raises the following exception:

Traceback (most recent call last):
  File "/home/flo/kruschkram/b3d-workspace/bugs/project.py", line 6, in <module>
    print(foo.vertices())
          ^^^^^^^^^^^^^^
  File "/home/flo/bin/cadquery/lib/python3.11/site-packages/build123d/topology.py", line 2117, in vertices
    [Vertex(downcast(i)) for i in self._entities(Vertex.__name__)]
                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/flo/bin/cadquery/lib/python3.11/site-packages/build123d/topology.py", line 2082, in _entities
    explorer = TopExp_Explorer(self.wrapped, inverse_shape_LUT[topo_type])
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: __init__(): incompatible constructor arguments. The following argument types are supported:
    1. OCP.TopExp.TopExp_Explorer()
    2. OCP.TopExp.TopExp_Explorer(S: OCP.TopoDS.TopoDS_Shape, ToFind: OCP.TopAbs.TopAbs_ShapeEnum, ToAvoid: OCP.TopAbs.TopAbs_ShapeEnum = <TopAbs_ShapeEnum.TopAbs_SHAPE: 8>)

Invoked with: None, <TopAbs_ShapeEnum.TopAbs_VERTEX: 7>

gumyr / build123d