Fix staging-debug artifact output expression

[ranade-oss]

Summary

Fixes the invalid GitHub Actions output reference that prevented ROSS staging release-train debug from registering and caused run 30236183908 to fail before creating jobs.

• rename the job output from artifact-upload to artifact_upload
• update the downstream reference to needs.debug.outputs.artifact_upload
• add executable baseline assertions that require the valid form and reject the invalid hyphenated dot-notation form
• refresh the exact-byte release manifest entries for the workflow and regression test

Validation

• final head: 0cf372fe4fc7bd7334482ca5043fe7e48c18e317
• final comparison against main: exactly three intended files changed
• release-manifest entry for tests/baseline/ross-staging-debug.test.mjs: 20,903 bytes, SHA-256 f6be049d97023ca7f01193d357dc02f4b5bb14c23fdf675f824961dfa2285d7d
• Baseline verification run 30237353946 passed, including the complete npm run check
• GitHub reports the PR as mergeable

Safety

• PR remains a GitHub draft
• no staging workflow was dispatched
• no production configuration or deployment was modified
• do not rerun staging until this PR is merged