chore(deps): update policyengine to 6.3.4

[policyengine]

Fixes #796

Summary

Update policyengine.py from 6.2.7 to 6.3.4 in the simulation API runtime.

The policyengine[models] requirement selects the runtime versions bundled by policyengine.py 6.3.4:

• policyengine-core: 3.33.0
• policyengine-us: 2.2.1
• policyengine-uk: 2.126.12
• spm-calculator: 1.0.0

The bundle also selects these certified data releases:

• US: populace-us-2024-spm-20260915
• UK: policyengine-uk-data-1.58.0

---

Generated automatically by GitHub Actions.

[MaxGhenis]

Merged at e9e117c on the standard gates.

• Purpose: the release step of the plan Max approved as d1482 (policyengine.py#604 → release → this update → deploy). policyengine 6.3.4 contains Dependency update workflow: run daily and append to the open PR instead of force-pushing #604, which points US state and district regions back at the national dataset so canonical SPM no longer refuses state-region runs (Beta deploy verification fails on three US simulations, blocking prod deploys since 9 Oct #747).
• Checks: all 11 passed on the head.
• Independent review (Opus 5.5): APPROVE.
  • The diff moves only the policyengine pin and the lock entries that follow from it: policyengine 6.2.7 → 6.3.4 and policyengine-uk 2.125.1 → 2.126.12.
  • Every changed wheel and sdist SHA-256 matches PyPI.
  • The 6.3.4 bundle manifest agrees with the PR body.

Superseded updater PRs #749, #769, #771 and #775 are closed in favour of this one.