Make header sticky

apps/app/src/features/openai/client/components/AiAssistant/AiAssistantChatSidebar/AiAssistantChatSidebar.tsx

@@ -241,7 +241,7 @@ const AiAssistantChatSidebarSubstance: React.FC<AiAssistantChatSidebarSubstanceP
   return (
     <>
       <div className="d-flex flex-column vh-100">
-        <div className="d-flex align-items-center p-3 border-bottom">
+        <div className="d-flex align-items-center p-3 border-bottom position-sticky top-0 bg-body z-1">
           <span className="growi-custom-icons growi-ai-chat-icon me-3 fs-4">ai_assistant</span>
           <h5 className="mb-0 fw-bold flex-grow-1 text-truncate">{currentThreadTitle ?? aiAssistantData.name}</h5>
           <button