Fix doc intro setext heading; reorder node feature columns

Add blank line before the rule so the intro renders as a paragraph, not a
setext H2.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/assets/MuSProt_documentation.md

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 # MuSProt Dataset Documentation
 
 **MuSProt** (Multistate Protein Database) is a million-scale multimodal database for multistate proteins, designed to support programmable protein design and AI model development. It links experimentally observed conformational states of identical protein sequences from the PDB, organizes them into state clusters and transition relationships, and enriches each record with structural similarity, experimental context, state-specific function rankings and transition fidelity labels. Users can search, browse and download MuSProt records to study conformational diversity, state-dependent functions and feasible protein state transitions.
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 ## Download