feat(mp): U3-1 医生端导航状态保持

- 新增 useNavigationState hook (saveDoctorPage/getDoctorLastPage)
- 首页医生重定向使用 getDoctorLastPage 代替硬编码路径
- 医生端工作台入口自动保存最后访问路径
- 医生再次打开首页时自动回到上次使用的医生端页面

apps/miniprogram/src/hooks/useNavigationState.ts

@@ -0,0 +1,43 @@
+import { useCallback } from 'react';
+import Taro from '@tarojs/taro';
+import { useAuthStore } from '@/stores/auth';
+
+const NAV_STATE_KEY = 'doctor_last_page';
+
+const DOCTOR_PAGES = [
+  '/pages/pkg-doctor-core/index',
+  '/pages/pkg-doctor-core/patients/index',
+  '/pages/pkg-doctor-core/consultation/index',
+  '/pages/pkg-doctor-core/followup/index',
+  '/pages/pkg-doctor-core/action-inbox/index',
+];
+
+export function saveDoctorPage(path: string): void {
+  if (!path.startsWith('/pages/pkg-doctor')) return;
+  try {
+    Taro.setStorageSync(NAV_STATE_KEY, path);
+  } catch { /* ignore */ }
+}
+
+export function getDoctorLastPage(): string {
+  try {
+    const saved = Taro.getStorageSync(NAV_STATE_KEY);
+    if (saved && typeof saved === 'string' && saved.startsWith('/pages/pkg-doctor')) {
+      return saved;
+    }
+  } catch { /* ignore */ }
+  return DOCTOR_PAGES[0];
+}
+
+export function useNavigationState() {
+  const isDoctor = useAuthStore((s) => s.isDoctor);
+
+  const navigateToDoctorHome = useCallback(() => {
+    if (!isDoctor()) return false;
+    const lastPage = getDoctorLastPage();
+    Taro.navigateTo({ url: lastPage });
+    return true;
+  }, [isDoctor]);
+
+  return { navigateToDoctorHome, saveDoctorPage, getDoctorLastPage };
+}