fix: null-guard animLayer and liveAnimCount in nextHop after destroy

Async timers (setInterval/setTimeout) started by animateHop() can fire
after destroy() has nulled animLayer and removed DOM elements. This
caused three console errors on the Live page when navigating away mid-
animation. Guards added at each async callback site.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

public/index.html

@@ -22,9 +22,9 @@
   <meta name="twitter:title" content="CoreScope">
   <meta name="twitter:description" content="Real-time MeshCore LoRa mesh network analyzer — live packet visualization, node tracking, channel decryption, and route analysis.">
   <meta name="twitter:image" content="https://raw.githubusercontent.com/Kpa-clawbot/corescope/master/public/og-image.png">
-  <link rel="stylesheet" href="style.css?v=1775062162">
-  <link rel="stylesheet" href="home.css?v=1775062162">
-  <link rel="stylesheet" href="live.css?v=1775062162">
+  <link rel="stylesheet" href="style.css?v=1775078686">
+  <link rel="stylesheet" href="home.css?v=1775078686">
+  <link rel="stylesheet" href="live.css?v=1775078686">
   <link rel="stylesheet" href="https://unpkg.com/leaflet@1.9.4/dist/leaflet.css"
     integrity="sha256-p4NxAoJBhIIN+hmNHrzRCf9tD/miZyoHS5obTRR9BMY="
     crossorigin="anonymous">
@@ -85,30 +85,30 @@
   <main id="app" role="main"></main>
 
   <script src="vendor/qrcode.js"></script>
-  <script src="roles.js?v=1775062162"></script>
-  <script src="customize.js?v=1775062162" onerror="console.error('Failed to load:', this.src)"></script>
-  <script src="region-filter.js?v=1775062162"></script>
-  <script src="hop-resolver.js?v=1775062162"></script>
-  <script src="hop-display.js?v=1775062162"></script>
-  <script src="app.js?v=1775062162"></script>
-  <script src="home.js?v=1775062162"></script>
-  <script src="packet-filter.js?v=1775062162"></script>
-  <script src="packets.js?v=1775062162"></script>
-  <script src="geo-filter-overlay.js?v=1775062162"></script>
-  <script src="map.js?v=1775062162" onerror="console.error('Failed to load:', this.src)"></script>
-  <script src="channels.js?v=1775062162" onerror="console.error('Failed to load:', this.src)"></script>
-  <script src="nodes.js?v=1775062162" onerror="console.error('Failed to load:', this.src)"></script>
-  <script src="traces.js?v=1775062162" onerror="console.error('Failed to load:', this.src)"></script>
-  <script src="analytics.js?v=1775062162" onerror="console.error('Failed to load:', this.src)"></script>
-  <script src="audio.js?v=1775062162" onerror="console.error('Failed to load:', this.src)"></script>
-  <script src="audio-v1-constellation.js?v=1775062162" onerror="console.error('Failed to load:', this.src)"></script>
-  <script src="audio-v2-constellation.js?v=1775062162" onerror="console.error('Failed to load:', this.src)"></script>
-  <script src="audio-lab.js?v=1775062162" onerror="console.error('Failed to load:', this.src)"></script>
-  <script src="live.js?v=1775062162" onerror="console.error('Failed to load:', this.src)"></script>
-  <script src="observers.js?v=1775062162" onerror="console.error('Failed to load:', this.src)"></script>
-  <script src="observer-detail.js?v=1775062162" onerror="console.error('Failed to load:', this.src)"></script>
-  <script src="compare.js?v=1775062162" onerror="console.error('Failed to load:', this.src)"></script>
-  <script src="node-analytics.js?v=1775062162" onerror="console.error('Failed to load:', this.src)"></script>
-  <script src="perf.js?v=1775062162" onerror="console.error('Failed to load:', this.src)"></script>
+  <script src="roles.js?v=1775078686"></script>
+  <script src="customize.js?v=1775078686" onerror="console.error('Failed to load:', this.src)"></script>
+  <script src="region-filter.js?v=1775078686"></script>
+  <script src="hop-resolver.js?v=1775078686"></script>
+  <script src="hop-display.js?v=1775078686"></script>
+  <script src="app.js?v=1775078686"></script>
+  <script src="home.js?v=1775078686"></script>
+  <script src="packet-filter.js?v=1775078686"></script>
+  <script src="packets.js?v=1775078686"></script>
+  <script src="geo-filter-overlay.js?v=1775078686"></script>
+  <script src="map.js?v=1775078686" onerror="console.error('Failed to load:', this.src)"></script>
+  <script src="channels.js?v=1775078686" onerror="console.error('Failed to load:', this.src)"></script>
+  <script src="nodes.js?v=1775078686" onerror="console.error('Failed to load:', this.src)"></script>
+  <script src="traces.js?v=1775078686" onerror="console.error('Failed to load:', this.src)"></script>
+  <script src="analytics.js?v=1775078686" onerror="console.error('Failed to load:', this.src)"></script>
+  <script src="audio.js?v=1775078686" onerror="console.error('Failed to load:', this.src)"></script>
+  <script src="audio-v1-constellation.js?v=1775078686" onerror="console.error('Failed to load:', this.src)"></script>
+  <script src="audio-v2-constellation.js?v=1775078686" onerror="console.error('Failed to load:', this.src)"></script>
+  <script src="audio-lab.js?v=1775078686" onerror="console.error('Failed to load:', this.src)"></script>
+  <script src="live.js?v=1775078686" onerror="console.error('Failed to load:', this.src)"></script>
+  <script src="observers.js?v=1775078686" onerror="console.error('Failed to load:', this.src)"></script>
+  <script src="observer-detail.js?v=1775078686" onerror="console.error('Failed to load:', this.src)"></script>
+  <script src="compare.js?v=1775078686" onerror="console.error('Failed to load:', this.src)"></script>
+  <script src="node-analytics.js?v=1775078686" onerror="console.error('Failed to load:', this.src)"></script>
+  <script src="perf.js?v=1775078686" onerror="console.error('Failed to load:', this.src)"></script>
 </body>
 </html>

public/live.js

@@ -1850,9 +1850,11 @@
     function nextHop() {
       if (hopIndex >= hopPositions.length) {
         activeAnims = Math.max(0, activeAnims - 1);
-        document.getElementById('liveAnimCount').textContent = activeAnims;
+        const countEl = document.getElementById('liveAnimCount');
+        if (countEl) countEl.textContent = activeAnims;
         return;
       }
+      if (!animLayer) return;
       // Audio hook: notify per-hop callback
       if (onHop) try { onHop(hopIndex, hopPositions.length, hopPositions[hopIndex]); } catch (e) {}
       const hp = hopPositions[hopIndex];
@@ -1865,11 +1867,11 @@
           }).addTo(animLayer);
           let pulseUp = true;
           const pulseTimer = setInterval(() => {
-            if (!animLayer.hasLayer(ghost)) { clearInterval(pulseTimer); return; }
+            if (!animLayer || !animLayer.hasLayer(ghost)) { clearInterval(pulseTimer); return; }
             ghost.setStyle({ fillOpacity: pulseUp ? 0.6 : 0.25, opacity: pulseUp ? 0.7 : 0.4 });
             pulseUp = !pulseUp;
           }, 600);
-          setTimeout(() => { clearInterval(pulseTimer); if (animLayer.hasLayer(ghost)) animLayer.removeLayer(ghost); }, 3000);
+          setTimeout(() => { clearInterval(pulseTimer); if (animLayer && animLayer.hasLayer(ghost)) animLayer.removeLayer(ghost); }, 3000);
         }
       } else {
         pulseNode(hp.key, hp.pos, typeName);

test-frontend-helpers.js

@@ -2696,6 +2696,34 @@ console.log('\n=== packets.js: savedTimeWindowMin defaults ===');
   });
 }
 
+// ===== live.js: nextHop null guards =====
+console.log('\n=== live.js: nextHop null guards ===');
+{
+  const liveSource = fs.readFileSync('public/live.js', 'utf8');
+
+  test('nextHop guards animLayer null before use', () => {
+    assert.ok(liveSource.includes('if (!animLayer) return;'),
+      'nextHop must return early when animLayer is null (post-destroy)');
+  });
+
+  test('nextHop setInterval guards animLayer null', () => {
+    assert.ok(liveSource.includes('if (!animLayer || !animLayer.hasLayer(ghost))'),
+      'setInterval in nextHop must guard animLayer null');
+  });
+
+  test('nextHop setTimeout guards animLayer null', () => {
+    assert.ok(liveSource.includes('if (animLayer && animLayer.hasLayer(ghost)) animLayer.removeLayer(ghost)'),
+      'setTimeout in nextHop must guard animLayer null');
+  });
+
+  test('nextHop guards liveAnimCount element null', () => {
+    assert.ok(liveSource.includes('const countEl = document.getElementById(\'liveAnimCount\')'),
+      'nextHop must null-check liveAnimCount element');
+    assert.ok(liveSource.includes('if (countEl) countEl.textContent = activeAnims'),
+      'nextHop must conditionally update liveAnimCount');
+  });
+}
+
 // ===== SUMMARY =====
 Promise.allSettled(pendingTests).then(() => {
   console.log(`\n${'═'.repeat(40)}`);