fix(footer): inconsistent icon sizes

## Description

The current footer implementation in `layout.tsx` has visibility and layout issues across different screen sizes, particularly mid / iPad range.

This issue proposes a full UI refactor for the footer to ensure it is responsive across all devices, while maintaining clean structure.

## Expected Behaviour

- No arbitrary widths, all icons are consistently sizes across different screen sizes while retaining aesthetic appeal

## Bonus

- Move the footer logic to a separate `Footer` component under the `components/` directory

## Images / Videos