[Good First Issue]: Add popular free developer coding fonts to shelf/perks.json #29

Task Summary

Add 3 prominent, high-legibility open-source developer fonts (JetBrains Mono, Fira Code, and Cascadia Code) to shelf/perks.json under the "Developer Fonts & Aesthetics" category.

Difficulty Level

🟢 Beginner (No code needed, JSON curation or documentation)

Context & Background

Developer tooling isn't just APIs and cloud credits — ergonomics, typography, and ligature support are essential parts of developer workstations.

Suggested Steps to Complete

1. Open shelf/perks.json.
2. Add entries for JetBrains Mono, Fira Code, and Cascadia Code with their official GitHub repos, ligatures details, and SIL Open Font License.
3. Validate using pnpm run validate and run pnpm run build.
4. Submit PR!

Relevant Files / Pointers

shelf/perks.json

Mentorship & Support

• Maintainers will review this PR within 24-48 hours and provide constructive feedback.
• Upon merge, the contributor will receive a shoutout on social channels and be featured in README!