add overflow detection to ethmarks-footer component

[ethmarks]

Add a script to ethmarks-footer that handles height overflow.

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[Copilot]

Pull Request Overview

This PR adds overflow detection functionality to the ethmarks-footer component to handle cases where page content exceeds the viewport height. The implementation detects when content overflows and applies appropriate CSS classes to enable responsive styling.

• Added height overflow detection logic that compares content height to viewport height
• Implemented ResizeObserver to monitor dynamic content changes
• Applied conditional CSS class management for overflow states

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