Add responsive fixes for the homepage and footer

[SusanGithaigaN]

Summary

The Extensions section on the homepage has responsive layout issues across medium and large breakpoints, affecting both the extensions wall and the footer.

Environment

Property	Value
Browser	Chrome (DevTools responsive mode)
Viewports tested	425px, 768px, 992px, 1024px, 1440px

Current behavior

Extensions section:

• The extensions wall is hidden or clipped on viewports between 425px and 1024px, instead of being contained within the section

Extra large screens (1440px):

Large through small screens (1024px–425px):

Footer:

• Text and icons are misaligned across large, medium, and small screen sizes

Extra large screens (1440px):

Large through small screens (1024px–425px):

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Steps to reproduce

1. Go to lnbits.com
2. Open browser DevTools and switch to responsive mode
3. Set viewport to 1440px, scroll to the Extensions section and note the layout
4. Resize to 1024px and observe the extensions wall being hidden or clipped
5. Continue resizing down through 992px to 425px and observe the layout at each step
6. Scroll to the Footer and observe text and icon alignment at each breakpoint

[SusanGithaigaN]

@arcbtc, @blackcoffeexbt, I'd like to work on fixing this