Add Gitea branch deletion fix references

[cookesan]

Adds Gitea branch deletion fix references to GHSA-rrcw-5rjv-vj26.

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-rrcw-5rjv-vj26/GHSA-rrcw-5rjv-vj26.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-rrcw-5rjv-vj26 and CVE-2025-68940 remain public and consistent with this advisory.
• Verified go-gitea/gitea PRs #32654 and #32707, commit 0d1fc2b2e98bc485c3a51dfa669a4896ffcd86d5, release v1.22.5, and the Go module proxy record for code.gitea.io/gitea v1.22.5.
• Local validation passed: jq empty and git diff --check.

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