fix: ResizeObserver leak, CSS class lowercase, active sessions live update

cmd/web-ui/static/app.js

@@ -13,6 +13,7 @@
   let dashboardState = null;
   let dashboardUnsubscribe = null;
   let dashboardChart = null;
+  let dashboardResizeObserver = null;
 
   function getWsURL() {
     const protocol = window.location.protocol === 'https:' ? 'wss:' : 'ws:';
@@ -81,6 +82,10 @@
       dashboardChart.destroy();
       dashboardChart = null;
     }
+    if (dashboardResizeObserver) {
+      dashboardResizeObserver.disconnect();
+      dashboardResizeObserver = null;
+    }
   }
 
   function route() {
@@ -1068,6 +1073,8 @@
     }
 
     if (dashboardState.summary) {
+      if (eventType === 'session.start') dashboardState.summary.active_sessions++;
+      if (eventType === 'session.end') dashboardState.summary.active_sessions = Math.max(0, dashboardState.summary.active_sessions - 1);
       if (eventType === 'run.start') dashboardState.summary.runs_today++;
       if (eventType === 'error') dashboardState.summary.errors_today++;
       if (eventType === 'span.end') {
@@ -1212,14 +1219,17 @@
 
     dashboardChart = new uPlot(opts, [timestamps, runs, tools, errors], container);
 
-    const ro = new ResizeObserver(entries => {
+    if (dashboardResizeObserver) {
+      dashboardResizeObserver.disconnect();
+    }
+    dashboardResizeObserver = new ResizeObserver(entries => {
       for (const entry of entries) {
         if (dashboardChart) {
           dashboardChart.setSize({ width: entry.contentRect.width, height: 200 });
         }
       }
     });
-    ro.observe(container);
+    dashboardResizeObserver.observe(container);
   }
 
   function appendToCurrentBucket(evt) {
@@ -1270,7 +1280,7 @@
     container.innerHTML = entries.map(([name, stats]) => {
       const total = stats.runs + stats.tools + stats.errors;
       const pct = maxTotal > 0 ? (total / maxTotal * 100) : 0;
-      const cssClass = name.replace(/[^a-z0-9-]/g, '-');
+      const cssClass = name.toLowerCase().replace(/[^a-z0-9-]/g, '-');
       return `
         <div class="fw-bar-row">
           <div class="fw-bar-label">