Add Python 3.14 support

[MaxGhenis]

Summary

Add Python 3.14 support to policyengine-core.

Status: Blocked on tables

⚠️ Waiting on PyTables/PyTables#1262 — tables doesn't have Python 3.14 wheels yet, and source builds fail. This blocks microsimulation functionality (loading CPS/microdata).

Once tables 3.11.0 ships with Python 3.14 support, this PR can be merged.

Changes

• Add Python 3.14 to classifiers in setup.py
• Add Python 3.14 to Test matrix in pr.yaml (3.12, 3.13, 3.14)
• Add Python 3.14 to SmokeTestForMultipleVersions matrix (3.10-3.14)
• Handle Python 3.14 like 3.13 for tables package workaround

What works now

• policyengine-core installs and runs on Python 3.14 ✅
• Household-level calculations work ✅

What's blocked

• Microsimulation (requires tables → policyengine-us-data → HDF5 microdata)

Dependencies

The numpy compatibility fix for Python 3.14 was already merged in PR #409.

Test plan

• CI runs tests on Python 3.10, 3.11, 3.12, 3.13, and 3.14
• Core tests pass on all versions
• Smoke tests with policyengine-us will pass once tables has 3.14 wheels

Related issue

Fixes #399

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 82.45%. Comparing base (58c2fca) to head (e162b83).
⚠️ Report is 31 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #425      +/-   ##
==========================================
+ Coverage   81.14%   82.45%   +1.31%     
==========================================
  Files         197      202       +5     
  Lines       10228    10585     +357     
  Branches     1057     1066       +9     
==========================================
+ Hits         8299     8728     +429     
+ Misses       1640     1582      -58     
+ Partials      289      275      -14     

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[nikhilwoodruff]

@MaxGhenis I've implemented a workaround to unblock this PR! 🎉

What changed

Instead of waiting for PyTables 3.11.0 to be released, I've updated the CI workflow to install PyTables directly from GitHub master for Python 3.14. This is similar to the existing Python 3.13 workaround, but uses:

pip install git+https://github.com/PyTables/PyTables.git@master

PyTables PR #1286 already merged Python 3.14 support on January 7, 2026, so the master branch has everything we need.

Changes made

Branch: claude/python-3.14-pytables-support-4cG3O

Updated .github/workflows/pr.yaml:

• Added Python 3.14 workaround that installs PyTables from GitHub
• Kept the existing Python 3.13 workaround intact
• Both test matrices now include Python 3.14

Updated setup.py:

• Added "Programming Language :: Python :: 3.14" classifier
• Updated comments to reflect Python 3.13+ requirements

Why this works

✅ PyTables master has Python 3.14 support (merged in PR #1286)
✅ Linux builds should work fine
⚠️ Windows 3.14 builds might have issues (PyTables excluded them due to test failures)
✅ Once PyTables 3.11.0 releases, we can remove the workaround and use the official wheels

Next steps

You can either:

1. Cherry-pick my commit (62f84e8e) into your add-python-3.14-support branch
2. Use my branch to update this PR
3. Wait for PyTables 3.11.0 if you prefer (but this workaround lets us test now)

The workaround follows the same pattern as the Python 3.13 handling, so it should be safe and maintainable until the official release.