Certify Populace fiscal target US release

[MaxGhenis]

Fixes #413.

Summary

• certify populace-us-2024-0cdbb27-c239dfe51c11-20260615T201302Z as the US default data release
• pin policyengine-us==1.729.0, matching the model package used to build the release
• update US release-manifest and trace TRO provenance to the tagged policyengine/populace-us release
• keep Populace diagnostics/source-coverage artifacts resolver-safe by using their release-scoped paths and validating vendored artifact reachability during certification
• update US region tests for the Populace-only bundle contract: political regions remain in the registry, but no inherited policyengine-us-data state/district H5s are exposed as certified region datasets

Release sanity

• release manifest validates with populace.data.contract.validate_release_dir
• policyengine.provenance.manifest.DataReleaseManifest validates the published manifest
• Hugging Face latest.json, release tag, and artifact hashes were verified after upload
• target surface: 457 hard targets: 1 CBO income-tax total, 400 IRS SOI rows, 51 state income-tax rows, and 5 JCT tax-expenditure rows
• source coverage diagnostics: CBO 1, IRS SOI 400, JCT 5, state income tax 51

Local runtime sanity

Using the released H5 with policyengine-us==1.729.0:

• income_tax: $2.260T, matching calibration diagnostics
• state_income_tax: $491.49B vs $494.88B summed state targets
• cdcc: $3.10B runtime aggregate; not part of the restored legacy JCT tax-expenditure target surface

Validation

• uv run ruff check src/policyengine/provenance/certification.py tests/test_certify_data_release.py tests/test_release_manifests.py tests/test_us_regions.py tests/test_models.py
• uv run ruff format --check src/policyengine/provenance/certification.py tests/test_certify_data_release.py tests/test_release_manifests.py tests/test_us_regions.py tests/test_models.py
• uv run python -m pytest tests/test_certify_data_release.py tests/test_release_manifests.py -q passed: 47 passed
• uv run python -m pytest -q passed: 635 passed, 46 warnings
• git diff --check