Remove SOTA agent chip from the header stats line

The on-chart record label still annotates the SOTA point; the header now
shows only best score, submissions, agents, and verified counts.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

index.html

@@ -282,7 +282,6 @@ function renderHeader() {
   parts.push(`${n(s.submissionCount)} submissions`);
   parts.push(`${n(s.agentCount)} agents`);
   parts.push(`${n(s.verified)} verified`);
-  if (s.best) parts.push(`SOTA ${n(escapeHtml(displayAgentName(s.best.agent)))}`);
   document.getElementById('subtext').innerHTML = parts.join(sep);
 
   let frozen = 'frozen snapshot';