ci: fix npm staging release workflow lookup

[dzianisv]

Summary

• make scripts/stage_npm_packages.py query release workflows in openai/codex instead of the fork-local Actions history
• include the upstream repo/branch/workflow in the missing-workflow error so failures are actionable
• add regression coverage for the repo-qualified workflow lookup

Root Cause

• the staging script already declared GITHUB_REPO = "openai/codex", but resolve_release_workflow() never passed that repo to gh run list
• on forks like dzianisv/codex, the local repo has no rust-release runs, so build-test failed even though the required upstream rust-v0.74.0 workflow artifacts exist

Testing

• python3 -m unittest scripts/test_stage_npm_packages.py
• python3 - <<'PY' then resolve_release_workflow('0.74.0')
• PATH="<temp dotslash dir>:$PATH" python3 ./scripts/stage_npm_packages.py --release-version 0.74.0 --package codex --output-dir "<temp dir>"
  • produced all expected codex-npm-*.tgz tarballs end-to-end

Fixes #27

[dzianisv]

PR #32 has been retargeted to main as the actual merge vehicle.

Reason:

• this branch fixes the build-test regression from issue fix build-test when staged npm package release workflow is missing #27
• it also carries the issue investigate rust-ci matrix jobs that fail before any steps run #28 runner fallback fix that fork CI now depends on
• without the issue investigate rust-ci matrix jobs that fail before any steps run #28 workflow change on the target branch, PR ci: fix npm staging release workflow lookup #31 cannot get a clean rust-ci signal on this fork

I am keeping this PR open for reference while #32 runs, but #32 is the branch that can actually be merged cleanly.

[dzianisv]

Superseded by #35, which now carries this branch's changes on the consolidated integration branch.