- Replace fixed width (max-w-56) with responsive viewport-based width
- Use 90vw on mobile and max-w-md on desktop for better adaptability
- Add vertical scrolling with max-h-64 overflow-y-auto
- Increase grid columns to 8 on medium+ screens for better space utilization
- Ensures all reactions are accessible regardless of quantity

Fixes #5117
Co-authored-by: GitHub Copilot <noreply@github.com>