hotfix: enhance assistant topic validation in useActiveTopic hook (#8213)

fix: enhance assistant topic validation in useActiveTopic hook

Updated the useActiveTopic hook to ensure that the assistant and its topics are properly validated before accessing properties. This prevents potential errors when data is not fully loaded.

src/renderer/src/hooks/useTopic.ts

@@ -34,7 +34,14 @@ export function useActiveTopic(assistantId: string, topic?: Topic) {
 
   useEffect(() => {
     // activeTopic not in assistant.topics
-    if (assistant && assistant.topics.length > 0 && !find(assistant.topics, { id: activeTopic?.id })) {
+    // 确保 assistant 和 assistant.topics 存在，避免在数据未完全加载时访问属性
+    if (
+      assistant &&
+      assistant.topics &&
+      Array.isArray(assistant.topics) &&
+      assistant.topics.length > 0 &&
+      !find(assistant.topics, { id: activeTopic?.id })
+    ) {
       setActiveTopic(assistant.topics[0])
     }
   }, [activeTopic?.id, assistant])