feat: add temporary learning resources to "start track" buttons #16

I noticed that the Learning Tracks section (Frontend Fundamentals, Modern React, Backend Engineering) includes "Start Track" buttons, but currently these buttons do not lead to any learning resources or pages.

Suggestion
While a full learning platform or curriculum system may still be under development, we could temporarily improve the user experience by linking these tracks to curated learning resources, such as high-quality YouTube tutorials or playlists.

This would allow community members to start learning immediately while the full system is being built.

Example approach
Each track could link to a curated set of beginner/intermediate/advanced resources:

• Frontend Fundamentals
• HTML & CSS fundamentals
• JavaScript basics
• DOM manipulation
• Modern React
• React fundamentals
• React Hooks
• Next.js basics
• Tailwind CSS
• Backend Engineering
• Node.js fundamentals
• API development
• PostgreSQL basics
• Docker introduction

These could initially point to trusted YouTube playlists or external documentation, and later be replaced with a dedicated learning platform or internal resources.

Benefits

1. Prevents the buttons from leading to empty or inactive pages
2. Provides immediate value to community members
3. Keeps the section functional until the full learning system is implemented

If this approach makes sense, I’d be happy to help:
curate resources, or implement the temporary links for each track.

Thanks!