adapt for QCSchema v2 and Python v3.14

[loriab]

Here's an adaptation for QCSchema v2 and Python 3.14. This and dftd4/dftd4#341 are counterparts. Please let me know of any changes you'd like.

• No change in compatibility with current (~v0.30) and recent QCElemental for Python <3.14 . These will continue to run QCSchema v1 only, and those QCElementals need Pydantic 1.10.17 or 2.x.
• With QCElemental >= v0.50.0rc3 (current available through -c conda-forge/label/qcelemental_dev, dftd3-python can run QCSchema v1 or v2 for all Pythons, except 3.14, where Pydantic retired the v1 API. Pydantic >=2.11 will be required (2.12 for Py 3.14). This can be seen in the test_qcschema patterns where 312 runs QCSchema v1 and skips 2, 313 runs both, and 314 runs 2 and skips v1, as illustrated in the dftd4 PR.
• The mac and windows wheel lanes were throwing errors like the below, so I updated to the latest cibuildwheel in the major series. Perhaps associated with [2.x] Update virtualenv URLs to avoid blob URLs pypa/cibuildwheel#2775

+ Download https://github.com/pypa/get-virtualenv/blob/20.26.4/public/virtualenv.pyz?raw=true to /Users/runner/Library/Caches/cibuildwheel/virtualenv-20.26.4.pyz Traceback (most recent call last):
...
File "/Library/Frameworks/Python.framework/Versions/3.14/lib/python3.14/urllib/request.py", line 611, in http_error_default raise HTTPError(req.full_url, code, msg, hdrs, fp) urllib.error.HTTPError: HTTP Error 429: Too Many Requests Error: Process completed with exit code 1.

• Sorry for hacking up the test file so extensively. Python 3.14 not being able to form QCSchema v1 models means I can't just take the v1 models and run .convert_v(2) on them to submit to run_qcschema. The diff is a little easier to read with whitespace tracking off.
• Associated with update to qcschema py314 conda-forge/dftd3-python-feedstock#33 and has been tested locally with QCEngine and Psi4
• I didn't try to impose qcel version constraints in pyproject.toml because qcel is optional, existing envs continue to work, and the new features will appear naturally when v0.50.0 moves beyond pre-release.

[codecov]

Codecov Report

❌ Patch coverage is 90.62500% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 65.87%. Comparing base (87efc01) to head (a57a472).

Files with missing lines	Patch %	Lines
python/dftd3/qcschema.py	90.62%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #170      +/-   ##
==========================================
+ Coverage   65.78%   65.87%   +0.08%     
==========================================
  Files          34       34              
  Lines        4782     4800      +18     
  Branches     1668     1668              
==========================================
+ Hits         3146     3162      +16     
- Misses        683      685       +2     
  Partials      953      953              

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