Add npm audit CI check to prevent future security vulnerabilities in react-frontend

[vmuralictr]

Problem

Issue #244 documented 55 vulnerabilities (1 critical, 27 high) in the
react-frontend. PR #277 addresses the current set, but without a CI
enforcement gate, new vulnerabilities will silently accumulate again
with future dependency updates.

Proposed Solution

Add npm audit --audit-level=high as a required GitHub Actions step
on all PRs that touch the react-frontend/ directory. This ensures
no PR introducing a high or critical severity vulnerability can be
merged without explicit review.

Implementation Plan

• Add a new job (or step) in .github/workflows/ scoped to
  react-frontend/ path changes
• Run npm audit --audit-level=high after npm ci
• Fail the check if high or critical vulnerabilities are found
• Document the audit policy in docs/Contribute.md

Why This Matters

Fixing vulnerabilities reactively is not sustainable. This change
makes security a first-class part of the PR review process for the
React frontend.

Relates to: #244, #277
Happy to guide anyone who picks this up.

[pleia2]

@TusharB-07 Thank you for your work on this!

I've sent an invite to join the project in the Triage role, can you accept that, and let me know so I can assign issues (like this) to you?

[TusharB-07]

@pleia2 I’ve accepted the Triage role invite, thank you for the opportunity! Please feel free to assign this or other issues to me — I’m happy to continue contributing to the project.