[FOSSOVERFLOW-25] Course Comparison Tool

[rajeev-sr]

Add a course comparison feature to help students make informed decisions by directly evaluating multiple courses side by side.

[rajeev-sr]

Proposed Features

• Side-by-Side Comparison: Compare up to 4 courses simultaneously.
• Visual Metrics: Charts comparing ratings, difficulty, and workload.
• Review Highlights: Surface key pros and cons from student reviews for each course.