Resolve npm audit vulnerabilities

[v1lling]

Currently seeing 24 npm vulnerabilities (1 critical, 16 high, 3 moderate, 4 low).

Main issues

• react-router-dom ^7.5.2 in package.json but project uses React 16 (v7 needs React 18+). This came from a Dependabot PR and blocks npm audit fix
• react-scripts@5.0.0 has multiple vulnerabilities in its dependencies

Proposed Solution

Phase 1 - Fix react-router-dom

• Downgrade react-router-dom to ^5.3.4 (React 16 compatible)
• Run npm audit fix to resolve fixable vulnerabilities
• Reduces vulnerabilities from 24 to 9

Phase 2 (Mid-term)

Consider migration from react-scripts to a more modern build tool, for example:

• Vite (faster, actively maintained)
• Or a plain webpack config
• Or update to React 18 with latest tooling

This would probably resolve the remaining 9 vulnerabilities and improve build performance.