Add GitHub Actions release build workflow

[tldev]

Summary

• add a manual GitHub Actions workflow for release builds on standard hosted runners
• stream the raw U.S. PBF into the canonical filter and hand off only the filtered artifact
• document the workflow and preserve release lineage with streamed-source metadata

Validation

• tooling/validate_repo.sh
• python3 -m unittest tooling.tests.test_export_release
• ruby -e "require 'yaml'; YAML.load_file('.github/workflows/release-build.yml')"