We're back down to a single working node, but this was a very practical
refactor.
In general, very good progress towards making #2 easy to fulfill in
its entirety.
Bugs remain:
- Category discovery has big code smells and needs smoothing. Blender
complains especially about wanting `_MT_` prefix/suffix on node
category submenu types. There's also a piece of registration logic in
category.py (big no no).
- I'd love to pass a `ruff`/`mypy` run before doubling down on node
creation, especially to help manage the complex pieces of MP logic.
- Still needs socket-bound unit-awareness feat. sympy units, before
doubling down on a data flow convention.
- Dependency management should also be smoothed out wrt. the user
experience, with cached directories exposed in addon preferences.
Solved a lot of problems related to bundled Python environment flushing
for reloading. However, we have a really solid framework for computing
node trees, and we can now both construct Tidy3D objects and noodle
them into the "Debug Printer". Next step is rote implementation of
relevant nodes, then live-visualization of the simulation setup.
See #2 for progress tracking.