Improve route handling and effect cleanup in `pages/_app.tsx`

[coderabbitai]

Description

The current implementation in pages/_app.tsx has several potential issues:

1. Direct access to location without checking for the window object.
2. Missing cleanup function in the useEffect hook.
3. Not using Next.js router for path detection.

References

• Pull Request: Use socials specs from markdown #7
• Comment: Use socials specs from markdown #7 (comment)
• Reported by: @luigibarbato