Coordinate local H5 workers with catalog requests

[anth-volk]

Fixes #985

Depends on #973. This PR is based on codex/h5-migration-pr8-worker-service so the diff only contains the PR 9 coordinator work.

Summary

• Move regional local H5 request enumeration onto USAreaCatalog and typed AreaBuildRequest payloads.
• Query the staged target database for congressional district targets and use the catalog to define the regional release shape.
• Partition typed weighted requests and send workers --requests-json payloads while keeping the legacy work_items_override path available.
• Normalize worker responses before coordinator error handling so protocol errors, worker failures, transport failures, and nonfatal issues are distinct.

Testing

• make lint
• uv run --no-sync pytest tests/unit/build_outputs/test_area_catalog.py tests/unit/build_outputs/test_partitioning.py tests/unit/build_outputs/test_worker_responses.py tests/unit/test_modal_local_area.py -q
• uv run --no-sync --with pyyaml python scripts/run_quality_guards.py
• uv run --no-sync --with pyyaml --with pytest pytest tests/unit/test_pipeline_docs_extractor.py tests/unit/test_pipeline_doc_guards.py -q