Merging NREL updates

I’ve prepared a snapshot import of the NREL fork into this public repo on branch migration/private-commits. It’s been a while since this code was tested on other datasets/clusters. This issue is a central place to document the major updates since the fork, coordinate testing, discuss gaps, and capture required changes before we merge into master.

**Next steps**
- Document major updates
- Collect feedback and test results here.
- Address action items
- When we’re confident, merge migration/private-commits to master