Implement GeometryTrees to contain and handle Regions

[aidanc-ansys]

Implement GeometryTrees, a subclass of dict, which contain GeometryNode, a subclass of Region. Each node contains direct pointers to its parent and child nodes, avoiding additional API calls.

[codecov]

Codecov Report

❌ Patch coverage is 97.14286% with 9 lines in your changes missing coverage. Please review.
✅ Project coverage is 85.82%. Comparing base (3a8c3f3) to head (890c0b0).
⚠️ Report is 7 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #545      +/-   ##
==========================================
- Coverage   88.46%   85.82%   -2.64%     
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  Files          21       23       +2     
  Lines        2583     3062     +479     
==========================================
+ Hits         2285     2628     +343     
- Misses        298      434     +136     

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[JackB-Ansys]

When I try this in the latest v2026R1 build with the e10 template, I get an error referring to the Endcap: "ValueError: 'Endcap' is not a valid RegionType"

This is the script I ran:
`import ansys.motorcad.core as pymotorcad

mc = pymotorcad.MotorCAD()

mc.load_template("e10")

geometry_tree = mc.get_geometry_tree()`

[aidanc-ansys]

I think the endcap issue should be fixed now: just a region type that seems to have slipped through the cracks and had never been added to the RegionType enumeration.

[JackB-Ansys]

Geometry tree nodes have the protected attribute _motorcad_instance. This seems to be None. Shouldn't it be the same as the geometry tree's mc attribute?

I found this because I wanted to unite some nodes, but had to set the _motorcad_instance first.

[aidanc-ansys]

Geometry tree nodes have the protected attribute _motorcad_instance. This seems to be None. Shouldn't it be the same as the geometry tree's mc attribute?

I found this because I wanted to unite some nodes, but had to set the _motorcad_instance first.

Yes! I hadn't actually noticed that they inherited such an attribute from Regions, so hadn't been setting it

[JackB-Ansys]

I have tested this out and it seems to work nicely. I've implemented the geometry tree functionality in this Adaptive Templates example: #555