Add http-proxy-middleware fix references

[cookesan]

Adds http-proxy-middleware fix references to GHSA-gcq2-9pq2-cxqm.

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-gcq2-9pq2-cxqm/GHSA-gcq2-9pq2-cxqm.json), JSON parses, git diff --check passes, and the exact-head worktree is clean.
• Revalidated the added public references and package-version evidence in the diff; all resolve through their source site or registry.

[cookesan]

Review note: this expands the http-proxy-middleware advisory with fixed release and npm package-version references, plus EOF newline normalization. Affected ranges, severity, and advisory metadata fields are unchanged. The v3.0.7 and v4.1.1 release URLs return 200, and npm confirms http-proxy-middleware@3.0.7 and http-proxy-middleware@4.1.1. The advisory JSON validates against the OSV schema.