chore(ci): bump actions/upload-artifact v4.6.2 → v7.0.1 (#3715) (#3716)

v4.6.2 ships a node20 runtime; GitHub Actions is deprecating Node 20
(removed from runners 2026-09-16). v7.0.1 ships node24 and is the last
Node-20 reference in the repo.

Pinned by full commit SHA per repo convention. Verified v5/v6/v7
breaking changes do not apply: artifact names are unique per workflow
run and neither step uses include-hidden-files.

Closes #3715

Co-authored-by: Claude Opus 4.7 <noreply@anthropic.com>