Pass Interstate relation cache into Release Build derive step

[tldev]

Problem

Release Build on GitHub produced 0 reference routes even when local full builds produced routes.

Root cause

The CI prefilter stage only passed a filtered PBF and source metadata into the host build step. The derive step did not receive the Interstate relation cache file required by the relation-backed corridor and route pipeline.

Fix

• tooling/ci/prefilter_stream.sh now also extracts interstate-relations.tsv from the raw source PBF.
• .github/workflows/release-build.yml now uploads and downloads the relation cache artifact.
• tooling/ci/build_release_host.sh now accepts --interstate-relation-cache-file and forwards it to openinterstate-derive via --interstate-relation-cache.

Validation

• bash -n tooling/ci/prefilter_stream.sh
• bash -n tooling/ci/build_release_host.sh
• tooling/validate_repo.sh