Functions: only show strings longer than 10 chars; remove chain composition from UI

- get_functions filters out annotations <= 10 chars.
- Remove Chain Composition from chain metadata block and the
alternative observations table (binding status retained; DB column,
backend field and docs unchanged).

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

backend/app/protein/tsv_loader.py

@@ -198,7 +198,7 @@ def get_functions(pdb_id: str, auth_asym_id: str) -> Optional[List[str]]:
     row = get_node_row(pdb_id, auth_asym_id)
     if row is None:
         return None
-    return _parse_functions(row["ranked_functions"])
+    return [f for f in _parse_functions(row["ranked_functions"]) if len(f) > 10]
 
 
 def get_state_id(pdb_id: str, auth_asym_id: str) -> Optional[str]:

frontend/src/components/datasets/protein/ChainBasicInfoCards.tsx

@@ -107,11 +107,6 @@ const ChainBasicInfoCards: React.FC<ChainBasicInfoCardsProps> = ({ metadata, isL
           <div className="text-sm font-semibold text-slate-900 capitalize">{metadata?.binding_status || '—'}</div>
         </div>
 
-        <div className="break-inside-avoid mb-3" style={{ breakInside: 'avoid' }}>
-          <div className="text-xs font-medium text-slate-500 uppercase tracking-wider mb-1">Chain Composition</div>
-          <div className="text-sm font-semibold text-slate-900 capitalize">{metadata?.chain_composition || '—'}</div>
-        </div>
-
         <div className="break-inside-avoid mb-3" style={{ breakInside: 'avoid' }}>
           <div className="text-xs font-medium text-slate-500 uppercase tracking-wider mb-1">CATH ID</div>
           <div className="text-sm font-semibold text-slate-900 font-mono">{metadata?.cath_id || 'uncategorized'}</div>

frontend/src/components/datasets/protein/DataTable.tsx

@@ -105,9 +105,6 @@ export const DataTable: React.FC<DataTableProps> = ({ data, loading, total, filt
               <th onClick={() => handleSort('binding_status')}>
                 Binding status {getSortIcon('binding_status')}
               </th>
-              <th onClick={() => handleSort('chain_composition')}>
-                Chain composition {getSortIcon('chain_composition')}
-              </th>
               <th onClick={() => handleSort('delta_rosetta')}>
                 ΔRosetta {getSortIcon('delta_rosetta')}
               </th>
@@ -163,9 +160,6 @@ export const DataTable: React.FC<DataTableProps> = ({ data, loading, total, filt
                 <td className="capitalize">
                   {record.binding_status || <span className="placeholder">—</span>}
                 </td>
-                <td className="capitalize">
-                  {record.chain_composition || <span className="placeholder">—</span>}
-                </td>
                 {(['delta_rosetta', 'delta_foldx', 'delta_evoef2', 'delta_rw', 'delta_rw_plus'] as const).map(field => {
                   const val = record[field];
                   return (