Add difFUBAR documentation to help.datamonkey.org

[stevenweaver]

Problem

difFUBAR is now live in beta but lacks comprehensive documentation on the help site.

Needed Documentation

1. Getting Started Guide

   • What is difFUBAR and when to use it
   • Input requirements (NEXUS format with embedded tree)
   • Branch group tagging requirements

2. Parameter Guide

   • Explanation of MCMC iterations
   • Grid points (if still user-controlled)
   • Branch set configuration

3. Results Interpretation

   • Understanding posterior probabilities
   • Reading the visualizations
   • Identifying significant sites

4. File Format Requirements

   • NEXUS format specifications
   • Tree embedding examples
   • Branch tagging syntax

5. Troubleshooting

   • Common error messages
   • File format issues
   • Performance considerations for large datasets

Context

From discussion: "I also need to add some documentation on http://help.datamonkey.org"

Priority

Medium - important for user adoption and reducing support requests

Dependencies

• Should be updated after UX improvements are implemented
• Coordinate with any changes to file upload workflow (separate tree upload)