Test and verify the constructor

[WorkGitAccount]

For the constructor task #86 , we worked in simultaneous development by implementing our own versions. This helped in double checking the build and module and calls were all working.

Now the constructor is done, want to verify through tests the expected sample data.

• [ ] discrete test case (squarepoissond case with 64 points coarsened to 16)
• [ ] demo test case (size n=400 in squarepoissond case)

[WorkGitAccount]

There remains a discrepancy between Python/Matlab when calling Coarsen() as shown in https://github.com/cs481-ekh/s24-meshers/issues/74#issuecomment-2069080215

This will cause the constructor's expected cases to fail.