更新BK缓存策略

src/lib/stock-api.ts

@@ -458,12 +458,12 @@ export interface SectorResponse {
  * 获取东方财富板块列表（按主力净流入排序）
  * @param type industry=行业板块, concept=概念板块
  */
-export async function fetchSectors(type: SectorType): Promise<SectorItem[]> {
+export async function fetchSectors(type: SectorType, signal?: AbortSignal): Promise<SectorItem[]> {
   const baseUrl = getApiBaseUrl();
   const url = `${baseUrl}/api/sectors?type=${type}`;
 
   try {
-    const resp = await fetch(url, { method: "GET" });
+    const resp = await fetch(url, { method: "GET", signal });
     if (!resp.ok) return [];
     const result: SectorResponse = await resp.json();
     return result.data || [];