Add Helium - Student Planner

[alexdlaird]

I'd like to add Helium to the Education section.

Helium is a color-coded student planner for classes, homework, grades, and notes with multi-device sync. It's built with Flutter, available on iOS, Android, and the web.

• Repo: https://github.com/HeliumEdu/frontend
• Website: https://www.heliumedu.com

[Xenon010101]

Hi, I am a GSSoC 2026 contributor and would like to work on this issue. This project matches my expertise. Please assign it to me.

/assign