fix(mp): 导航/请求健壮性 — reLaunch 去重 + 失败降级

- navigateToLogin 添加去重 + reLaunch 失败降级 redirectTo
- request.ts safeReLaunch 添加目标页检测 + 失败降级
- 退出登录 reLaunch 失败降级 redirectTo
- DoctorTabBar / 首页医生端跳转 reLaunch 失败降级
- 网络恢复时正确清理 toast 状态和定时器

apps/miniprogram/src/stores/auth.ts

@@ -293,6 +293,9 @@ export const useAuthStore = create<AuthState>((set, get) => ({
     });
     resetAllStores();
     set({ user: null, roles: [], currentPatient: null, patients: [] });
-    Taro.reLaunch({ url: '/pages/index/index' });
+    Taro.reLaunch({ url: '/pages/index/index' }).catch((err) => {
+      console.warn('[auth] reLaunch after logout failed:', err);
+      Taro.redirectTo({ url: '/pages/index/index' }).catch(() => {});
+    });
   },
 }));