style(web): skip row-hover highlight on empty-state rows

Hovering the empty-state row in LiveLogs/Dashboard tables briefly lit
the full-width td with the data-row glow. Tag the placeholder tr with
.empty-row and scope the .logs-table hover rule to :not(.empty-row).

decnet_web/src/components/Dashboard.css

@@ -372,7 +372,7 @@
   border-bottom: 1px solid rgba(48, 54, 61, 0.5);
 }
 
-.logs-table tr:hover {
+.logs-table tr:not(.empty-row):hover {
   background-color: rgba(0, 255, 65, 0.03);
 }
 

decnet_web/src/components/Dashboard.tsx

@@ -417,7 +417,7 @@ const Dashboard: React.FC<DashboardProps> = ({ searchQuery }) => {
                     </tr>
                   );
                 }) : (
-                  <tr>
+                  <tr className="empty-row">
                     <td colSpan={6} style={{ padding: 0 }}>
                       <EmptyState
                         icon={Activity}

decnet_web/src/components/LiveLogs.tsx

@@ -360,7 +360,7 @@ const LiveLogs: React.FC = () => {
                   </tr>
                 );
               }) : (
-                <tr>
+                <tr className="empty-row">
                   <td colSpan={5}>
                     <EmptyState
                       icon={Radio}