Add link hover preview to status bar

[ptheofan]

Summary

This PR adds a feature that displays the target URL of hovered links in the status bar, improving the user experience when viewing rendered markdown documents.

Key Changes

• Renderer: Added setupLinkHover() method to track mouse events over links and update the status bar with the target URL
• StatusBar:
  • Added linkUrl property to the state
  • Implemented setLinkUrl() method to update the link display
  • Added #status-link element reference and initialization
• Styling: Added .status-link CSS class with ellipsis truncation for long URLs and hide-when-empty behavior
• HTML: Added status link element to the status bar footer
• Documentation: Updated CHANGELOG with the new feature

Implementation Details

• The link hover detection uses event delegation with mouseover, mouseout, and mouseleave events on the viewer container
• Links are identified using closest('a[href]') to handle clicks on nested elements within links
• The status bar element is hidden when empty using CSS (:empty pseudo-selector)
• Long URLs are truncated with ellipsis, limited to 60 characters width
• The implementation properly cleans up by clearing the link URL on mouseleave

https://claude.ai/code/session_0174FZDHzmNESyHbFdbd3giP