Show parallel-role count in LabStatusStrip

When multiple specialists run in parallel, the strip now reads
"active: Analytical (+2 more)" instead of a single role name —
matches the parallel-role tracking added to useLiveLabEvents in the
prior commit.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: HaibaraAi137

frontend/src/App.tsx

@@ -292,6 +292,7 @@ export function App() {
                 mode={labMode}
                 project={liveProject}
                 activeRoleLabel={liveLab.activeRole?.role ?? null}
+                activeRoleCount={liveLab.activeRoles.length}
               />
             </div>
           </div>
@@ -383,9 +384,15 @@ interface LabStatusStripProps {
     | null
     | undefined;
   activeRoleLabel: string | null;
+  activeRoleCount?: number;
 }
 
-function LabStatusStrip({ mode, project, activeRoleLabel }: LabStatusStripProps) {
+function LabStatusStrip({
+  mode,
+  project,
+  activeRoleLabel,
+  activeRoleCount,
+}: LabStatusStripProps) {
   if (mode === "demo" || !project) {
     // Default state — no project bound, just hint.
     return (
@@ -403,7 +410,13 @@ function LabStatusStrip({ mode, project, activeRoleLabel }: LabStatusStripProps)
         live
         <span>iter #{project.iteration_count ?? "—"}</span>
         <span>{tokens.toLocaleString()} tokens</span>
-        <span>{activeRoleLabel ? `active: ${activeRoleLabel}` : "warming up..."}</span>
+        <span>
+          {activeRoleLabel
+            ? activeRoleCount && activeRoleCount > 1
+              ? `active: ${activeRoleLabel} (+${activeRoleCount - 1} more)`
+              : `active: ${activeRoleLabel}`
+            : "warming up..."}
+        </span>
       </span>
     );
   }