Add Langflow logout advisory references

[cookesan]

Adds Langflow logout advisory references to GHSA-7hw8-6q6r-4276.

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-7hw8-6q6r-4276/GHSA-7hw8-6q6r-4276.json), JSON parses, git diff --check passes, and the exact-head worktree is clean.
• Revalidated the added public references in the diff; all resolve through their source site or registry.

[cookesan]

Refreshed on July 8, 2026:

• GHSA-7hw8-6q6r-4276 and CVE-2026-55423 remain public and consistent with this advisory.
• Verified langflow-ai/langflow PRs #10527 and #10528, commits d3f95a3b6cadcb09f402e058e74ed393a3ef5579 and 537e096e826e018314ea3abaca65256f9a39787e, release v1.7.1, and PyPI langflow 1.7.1.
• Added the NVD advisory reference and nvd_published_at value after confirming the public NVD record.
• Local validation passed: jq empty and git diff --check.

No affected range, package, or severity changes are included.