fix(frontend): 30 high-severity npm-audit vulns reddening Security Scanning repo-wide (postcss/serve/minimatch)

[cristim]

Security Scanning red repo-wide: 30 high-severity frontend npm-audit vulns

npm audit in the frontend now exits 1 with 30 high-severity advisories, failing the Security Scanning job (and therefore the CI Success gate) on every open PR, including trivial ones that don't touch the frontend.

Not a code regression: Security Scanning was green on main as of 2026-07-23 (d9eb097) with the same package-lock.json. The npm advisory database has since published new advisories, so npm audit now flags dependencies that were clean 3 days ago.

Advisories (high)

• postcss <=8.5.17 — Path Traversal in source-map auto-loading (GHSA-r28c-9q8g-f849). fix available via npm audit fix.
• serve / serve-handler / minimatch — chain of high-severity deps.
• (30 high total; run npm audit in the frontend for the full list.)

Fix (per owner no-masking-CI-debt directive: fix for real, do not suppress)

1. In the frontend dir: npm audit fix (semver-compatible) first; re-run npm audit + npm run build + the frontend test/lint to confirm nothing breaks.
2. For anything remaining that needs npm audit fix --force (major bumps of postcss/serve/etc.): assess each breaking change, bump deliberately, and verify the build + a smoke test of the affected UI.
3. Do NOT gate-suppress (no --audit-level bump, no || true, no removing the audit step).

Impact

Blocks merge of all current PRs (#1495, #1504, and any future) until resolved, since CI Success aggregates Security Scanning.

Related

Surfaced while merge-checking the MCP PRs (#1495, #1504), neither of which touches the frontend.