Add js-yaml merge key fix references

[cookesan]

Adds js-yaml merge key fix references to GHSA-h67p-54hq-rp68.

Audit refresh, July 8, 2026:

• Confirmed the live PR is open, ready for review, merge-clean, and the visible advisory check is green.
• Rechecked the merge-base diff: exactly one advisory JSON file changes (advisories/github-reviewed/2026/06/GHSA-h67p-54hq-rp68/GHSA-h67p-54hq-rp68.json), JSON parses, git diff --check passes, and the exact-head worktree is clean.
• Revalidated the added public references and package-version evidence in the diff; all resolve through their source site or registry.

[cookesan]

Maintainer audit: this only expands the reference set for the js-yaml merge key advisory. The three upstream commits resolve, npm records for js-yaml 4.2.0 and 3.15.0 resolve, and CVE-2026-53550 is present in NVD. The advisory JSON parses, the committed diff passes git diff --check, the PR is merge-clean, and advisory processing is successful. No package, affected ranges, severity, or database metadata is changed.