fix: resolve tar security vulnerability in website (#600)

## Summary
- Adds yarn resolutions to fix high-severity tar vulnerability (requires
7.5.7)
- Resolves Dependabot alert #67

## Test plan
- [x] `yarn npm audit --all` shows no audit suggestions
- [x] CI passes

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

Author: B4nan