Add Gitea explore users fix references

[cookesan]

Adds Gitea explore users fix references to GHSA-jhx5-4vr4-f327.

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/2025/12/GHSA-jhx5-4vr4-f327/GHSA-jhx5-4vr4-f327.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-jhx5-4vr4-f327 and CVE-2025-68943 remain public and consistent with this advisory.
• Verified go-gitea/gitea PRs #29430 and #29443, commit 2b059f493e46b8b0fb52492623e36a8375cb5fbb, release v1.21.8, and the Go module proxy record for code.gitea.io/gitea v1.21.8.
• Local validation passed: jq empty and git diff --check.

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