XFSkins - Dark Mode Toggle 1.0.0

XenForo's default style variation structure with dark/light options can sometimes create unnecessary links and menu clutter. This can lead to search engines crawling `misc/style-variation` links more frequently.

This plugin uses the existing XenForo variation system to transform this area into a single-button toggle.

Features:
- One-click toggle between light/dark mode
- Simple toggle structure with moon/sun icons
- Preserves the style selector
- Shows only to logged-in members
- `rel="nofollow"` support
- XenForo 2.3+ compatibility

Advantages:
- Simpler user experience
- Cleaner footer/header appearance
- Helps reduce unnecessary crawling of `misc/style-variation` links
- Contributes to lowering crawl/error density in Google Search Console