Add parse-server file extension XSS advisory references

[cookesan]

Adds parse-server file extension XSS advisory references to GHSA-v8x7-r927-cc93.

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-v8x7-r927-cc93/GHSA-v8x7-r927-cc93.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]

Rechecked this reference-only PR while keeping the open Advisory Database queue current.

Adds direct commit and release references for GHSA-v8x7-r927-cc93 in both Parse Server release lines. The advisory already references upstream PR #10505 and PR #10506 plus package source; this PR links each merged fix to its fixed release.

Current audit, July 8, 2026:

• GHSA-v8x7-r927-cc93 is live and not withdrawn.
• NVD currently returns no record for CVE-2026-55778, so this PR does not add an NVD reference.
• PR #10505 merged to alpha as commit be12a60d65b6e140481882037fb896b1f951df50; release 9.9.1-alpha.11 is published, marked prerelease, and not marked draft.
• PR #10506 merged to release-8.x.x as commit 97c6a78d19f976ec756c1295f08a8fccab90799a; release 8.6.81 is published and not marked draft or prerelease.
• npm parse-server 9.9.1-alpha.11 and 8.6.81 both resolve with package tarball and integrity metadata.
• Local JSON validation and whitespace checks pass, and the diff only changes this advisory.

No advisory data fields are changed.