Implemented all 9 UI fixes across health charts and activity detail pages. Changes are ready to push to git for the Docker build to pick them up.

frontend/src/pages/RecordsPage.jsx

@@ -226,8 +226,9 @@ function SegmentRecords() {
     enabled: !!selectedRouteId,
   })
 
-  const theoreticalBest = bests?.length && bests.every(b => b.best_s != null)
-    ? bests.reduce((sum, b) => sum + b.best_s, 0)
+  const kmBests = (bests || []).filter(b => b.name?.startsWith('km '))
+  const theoreticalBest = kmBests.length && kmBests.every(b => b.best_s != null)
+    ? kmBests.reduce((sum, b) => sum + b.best_s, 0)
     : null
 
   if (!routes?.length) return (
@@ -314,7 +315,7 @@ function SegmentRecords() {
             </table>
             {theoreticalBest != null && (
               <div className="flex items-center justify-between px-4 py-3 border-t border-gray-800 bg-gray-900/60">
-                <span className="text-xs text-gray-500">Theoretical best (sum of all segment bests)</span>
+                <span className="text-xs text-gray-500">Theoretical best (1km splits only)</span>
                 <span className="font-mono text-sm font-semibold text-blue-400">{formatDuration(theoreticalBest)}</span>
               </div>
             )}