perf: CompanyOverview 内层 Tab 懒加载优化

- 将 useCompanyOverviewData（9个API）拆分为独立 Hooks：
  - useBasicInfo: 基本信息（首屏唯一加载）
  - useShareholderData: 股东信息（4个API）
  - useManagementData: 管理层信息
  - useAnnouncementsData: 公告数据
  - useBranchesData: 分支机构
  - useDisclosureData: 披露日程
- BasicInfoTab 使用子组件实现真正的懒加载：
  - ShareholderTabPanel、ManagementTabPanel 等
  - 配合 Chakra UI isLazy，切换 Tab 时才加载数据
- 首屏 API 请求从 9 个减少到 1 个

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/views/Company/components/CompanyOverview/hooks/useAnnouncementsData.ts

@@ -0,0 +1,61 @@
+// src/views/Company/components/CompanyOverview/hooks/useAnnouncementsData.ts
+// 公告数据 Hook - 用于公司公告 Tab
+
+import { useState, useEffect, useCallback } from "react";
+import { logger } from "@utils/logger";
+import { getApiBase } from "@utils/apiConfig";
+import type { Announcement } from "../types";
+
+const API_BASE_URL = getApiBase();
+
+interface ApiResponse<T> {
+  success: boolean;
+  data: T;
+}
+
+interface UseAnnouncementsDataResult {
+  announcements: Announcement[];
+  loading: boolean;
+  error: string | null;
+}
+
+/**
+ * 公告数据 Hook
+ * @param stockCode - 股票代码
+ */
+export const useAnnouncementsData = (stockCode?: string): UseAnnouncementsDataResult => {
+  const [announcements, setAnnouncements] = useState<Announcement[]>([]);
+  const [loading, setLoading] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+
+  const loadData = useCallback(async () => {
+    if (!stockCode) return;
+
+    setLoading(true);
+    setError(null);
+
+    try {
+      const response = await fetch(
+        `${API_BASE_URL}/api/stock/${stockCode}/announcements?limit=20`
+      );
+      const result = (await response.json()) as ApiResponse<Announcement[]>;
+
+      if (result.success) {
+        setAnnouncements(result.data);
+      } else {
+        setError("加载公告数据失败");
+      }
+    } catch (err) {
+      logger.error("useAnnouncementsData", "loadData", err, { stockCode });
+      setError("网络请求失败");
+    } finally {
+      setLoading(false);
+    }
+  }, [stockCode]);
+
+  useEffect(() => {
+    loadData();
+  }, [loadData]);
+
+  return { announcements, loading, error };
+};