feat(dashboard): show per-chip question counts in filter row

Previously only the 'all' chip showed a count (all · N). The operator
had to click each chip to see how many questions were in each category.

Now every chip shows its own count:
  all · 5   @operator · 2   @peer · 3   @agentname · 1

This lets the operator see the distribution at a glance and navigate
directly to whichever category has pending items without guessing.

frontend/packages/dashboard/src/tabs.js

@@ -1863,13 +1863,20 @@ window.marked = marked;
       b.addEventListener('click', () => setQuestionsFilter(value));
       return b;
     };
+    // Count pending questions per filter value so each chip shows its
+    // own hit count — the operator can see "operator · 2 / peer · 3"
+    // at a glance without clicking through each tab.
+    const operatorCount = allPending.filter((q) => !q.target).length;
+    const peerCount     = allPending.filter((q) => !!q.target).length;
+    const agentCount    = (name) => allPending.filter(
+      (q) => q.asker === name || q.target === name).length;
     filterRow.append(
-      mkChip('all', `all · ${allPending.length}`),
-      mkChip('operator', '@operator'),
-      mkChip('peer', '@peer'),
+      mkChip('all',      `all · ${allPending.length}`),
+      mkChip('operator', `@operator · ${operatorCount}`),
+      mkChip('peer',     `@peer · ${peerCount}`),
     );
     for (const name of Array.from(participants).sort()) {
-      filterRow.append(mkChip('agent:' + name, '@' + name));
+      filterRow.append(mkChip('agent:' + name, `@${name} · ${agentCount(name)}`));
     }
 
     // Evict resolved/cancelled questions from the row cache.