fix(sessions): avatar da conta em círculo (rounded-full)

O avatar/foto do número em /sessions estava rounded-2xl (quadrado arredondado);
passa a rounded-full (círculo), com a foto (object-cover) preenchendo.

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

frontend/views/newwhats/SessionsView.tsx

@@ -358,7 +358,7 @@ const SessionCard = React.forwardRef<HTMLDivElement, {
 
       <div className="flex items-start justify-between relative z-10">
         <div className="flex items-center gap-4">
-          <div className={`w-14 h-14 rounded-2xl overflow-hidden flex items-center justify-center border-2 shadow-lg ${isConnected ? 'bg-emerald-500/10 border-emerald-500/30 text-emerald-400' : 'bg-gray-50 border-gray-200 text-gray-500'}`}>
+          <div className={`w-14 h-14 rounded-full overflow-hidden flex items-center justify-center border-2 shadow-lg ${isConnected ? 'bg-emerald-500/10 border-emerald-500/30 text-emerald-400' : 'bg-gray-50 border-gray-200 text-gray-500'}`}>
             {inst.avatar
               ? <img src={inst.avatar} alt={inst.name} className="w-full h-full object-cover" onError={(e) => { (e.currentTarget as HTMLImageElement).style.display = 'none'; (e.currentTarget.nextSibling as HTMLElement)?.style.setProperty('display', 'flex') }} />
               : null}