Add Gitea basic auth scope fix references

[cookesan]

Adds Gitea basic auth scope fix references to GHSA-9r5x-wg6m-x2rc.

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-9r5x-wg6m-x2rc/GHSA-9r5x-wg6m-x2rc.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]

Maintainer audit: this only expands the reference set for the Gitea basic auth scope advisory. go-gitea/gitea#37486 and the release/v1.26 backport #37503 are merged, release-branch commit b88bad2a01cc5fb7a74d607551e9abd9e9596e44 resolves, and the v1.26.2 release blog, release tag, and Go module record resolve. The advisory JSON parses, the committed diff passes git diff --check, the PR is merge-clean, and advisory processing is successful. No package, affected range, severity, or database metadata is changed.