Add longwise local geography weights

[MaxGhenis]

Summary

• add long_geography.py, an OA-first long local-geography sidecar with source-household provenance and support diagnostics
• wire routine builds/uploads/downloads/manifests to include local_geography_weights.csv.gz without expanding dense local-area H5 matrices
• keep a guarded small-diagnostic path for explicit dense H5 to long conversion, while steering production toward assigned geography and future 1D L0/local weights
• share the area-to-household index resolver with local H5 publishing and preserve source_year / source_household_id through clone-and-assign

Testing

• python3 -m ruff check policyengine_uk_data/calibration/long_geography.py policyengine_uk_data/tests/test_long_geography.py policyengine_uk_data/calibration/publish_local_h5s.py policyengine_uk_data/datasets/create_datasets.py policyengine_uk_data/storage/download_completed_datasets.py policyengine_uk_data/storage/upload_completed_datasets.py policyengine_uk_data/tests/test_release_manifest.py policyengine_uk_data/utils/release_manifest.py policyengine_uk_data/calibration/clone_and_assign.py
• uv run --frozen pytest policyengine_uk_data/tests/test_long_geography.py policyengine_uk_data/tests/test_publish_local_h5s.py policyengine_uk_data/tests/test_release_manifest.py policyengine_uk_data/tests/test_clone_and_assign.py -q

Note

This is a bridge for migration off the matrix path. The long-term owner should be Populace: compact UK remains the fast default dataset, and a future populace-data variant="local" artifact can carry pooled-FRS / clone-and-assign / L0 local geography.