Fix Vue template syntax error in dynamic class binding

- Fix session card class binding: change from object to array syntax
- Allow proper dynamic class generation for status-based styling

frontend/src/components/CollaborativeInput.vue

@@ -186,7 +186,7 @@ const removeFile = () => {
               :key="session.sessionId"
               @click="handleOpenSession(session.sessionId)"
               class="session-card-horizontal"
-              :class="{ 'status-' + session.status }"
+              :class="['status-' + session.status]"
               :title="session.prompt"
             >
               <div class="card-left">