[codex] add Vitest to project suggestions

[Sean-Kenneth-Doherty]

Summary

• add Vitest to the project suggestions list
• link the card to the Vitest GitHub contributor page
• include GitHub avatar, concise description, and testing/framework tags

Validation

• GitHub API reports vitest-dev/vitest is public, unarchived, and on main
• https://github.com/vitest-dev/vitest/contribute returns HTTP 200
• https://avatars.githubusercontent.com/u/95747107?v=4 returns HTTP 200
• vitest-dev/vitest has an open help wanted issue
• Vitest source count is 1 via src/data/projects.js import
• git diff --check
• GITHUB_TOKEN=$(gh auth token) pnpm build
• generated dist/index.html contained the Vitest card and contributor link before restoring generated files

Addresses #1

[Sean-Kenneth-Doherty]

Closing this to reduce maintainer review noise from my project-suggestion-only PR batch. I am pruning these so the queue can focus on concrete bug, security, accessibility, and performance fixes.