Require PolicyEngine 6.2.7 for regional simulations

[anth-volk]

Fixes #3864

Summary

• Require published policyengine[models]==6.2.7 in the API runtime and generic container image, and regenerate the frozen lockfile for that release.
• Use the bundle's exact Core 3.33.0, US 2.2.1, UK 2.125.1 and SPM calculator 1.0.0 requirements; do not select country packages independently.
• Verify that the national US default remains populace_us_2024, and that states and congressional districts use the certified populace_us_2024_acs_local dataset through standard region_datasets metadata rather than dataset_overlays.
• Update complete installed-catalog expectations for the 6.2.7 bundle.
• Support England's multi-value region filter in catalog extraction. Flat list/tuple membership values are stored as compact JSON arrays in the existing text column; scalar values retain their previous representation. Invalid, empty, nested or oversized membership values fail before database access.
• Assert that the real installed England filter retains all nine English regions.
• Update the existing bundle changelog fragment.

Dependency and merge order

Rebased onto API master at 21ddf3476f801d09239dc49e6352c756800f63ee.

PolicyEngine 6.2.7 is published and retains the certified regional mappings from PolicyEngine/policyengine.py#552 and the temporary ACS WIC participation fix from #566. The runtime declarations, generic Docker pin and generated lockfile all request 6.2.7; no pending-publication dependency mismatch remains.

PolicyEngine/policyengine-sim-api#746 already updated simulation main to 6.2.7. The remaining regional metadata and Stage 12 integration is PolicyEngine/policyengine-sim-api#726. Merge and successfully deploy #726 before this API PR. The existing simulation-bundle compatibility requirement is unchanged and must confirm support for 6.2.7 before API deployment.

Catalog compatibility

The real 6.2.7 import exposed England's membership filter: its variable_value is a list of nine UK regions, not a scalar. The importer now preserves the complete list without a schema migration. Both existing SQLModel columns remain unchanged, including their 255-character limit.

The installed catalog contains 7,275 variables, 29,299 parameter nodes, 104,140 parameters, 1,193,952 parameter values, three datasets and 826 regions. Exact count assertions remain in the integration test so future country-package changes require explicit review.

Validation after update

• Installed the regenerated frozen environment and confirmed PolicyEngine 6.2.7 and its certified country/core dependencies.
• Constants and catalog-extraction unit tests: 69 passed.
• Catalog publication and metadata-service unit tests: 25 passed.
• Complete installed-catalog compatibility test, including exact counts, regional dataset selection and the nine-region England filter: passed.
• uv lock --check, changed-file Ruff lint, repository formatting and git diff --check: passed.
• Migration quality guards: passed. Regenerated migration-contract artifacts have no tracked changes.
• The complete API suite, database-backed integration suite, container builds and live deployment checks were not run manually for this update.

Deployment scope

Existing Flask/API v1 routes and compute delegation remain in place. This change introduces no route cutover, public HTTP schema change, Alembic revision, database provisioning, environment variable, secret, service account or deployment target. No running infrastructure or traffic was modified.

[codecov]

Codecov Report

❌ Patch coverage is 60.00000% with 6 lines in your changes missing coverage. Please review.
✅ Project coverage is 45.25%. Comparing base (21ddf34) to head (3c7c0e7).

Files with missing lines	Patch %	Lines
policyengine_api/data/v2/catalog/extraction.py	60.00%	4 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3868      +/-   ##
==========================================
+ Coverage   45.22%   45.25%   +0.02%     
==========================================
  Files         183      183              
  Lines       11073    11085      +12     
  Branches     1905     1907       +2     
==========================================
+ Hits         5008     5016       +8     
- Misses       5644     5647       +3     
- Partials      421      422       +1     

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