Shorten publication run identifiers

[anth-volk]

Fixes #981

Summary

• Drop the source SHA from generated publication run IDs.
• Use us-data as the default Modal app prefix and scope app names by candidate version plus run ID.
• Fix new-run metadata construction so release context fields are only passed once.

Expected naming

• Run ID: usdata-gha25865360265-a1
• Modal app: us-data-1-115-2-patch-usdata-gha25865360265-a1
• HF staging: staging/1.115.2-patch-usdata-gha25865360265-a1

Testing

• make lint
• ruff check .github/scripts/resolve_run_context.py modal_app/pipeline.py policyengine_us_data/utils/run_context.py tests/unit/test_pipeline.py tests/unit/test_run_context.py tests/unit/test_release_manifest.py tests/unit/test_modal_local_area.py tests/unit/version_manifest/test_version_manifest.py tests/unit/calibration/test_compare_calibration_runs.py tests/unit/test_remote_calibration_runner.py tests/unit/calibration/test_chunked_matrix_modal.py
• ruff format .github/scripts/resolve_run_context.py modal_app/pipeline.py policyengine_us_data/utils/run_context.py tests/unit/test_pipeline.py tests/unit/test_run_context.py tests/unit/test_release_manifest.py tests/unit/test_modal_local_area.py tests/unit/version_manifest/test_version_manifest.py tests/unit/calibration/test_compare_calibration_runs.py tests/unit/test_remote_calibration_runner.py tests/unit/calibration/test_chunked_matrix_modal.py --check
• uv run --no-sync --with pyyaml python scripts/run_quality_guards.py
• Focused pytest batch: 124 passed, 1 skipped; one unrelated rollback test failed because the temporary no-sync env lacked installed policyengine-us
• Targeted version-manifest run ID tests passed separately