fix(mp): P1+P2 稳定性加固 — 导航安全+生产日志+分包预加载+logout清理

P1:
- 全局 23 个页面 Taro.navigateTo → safeNavigateTo，防止页栈超10层
- 生产构建保留 console.warn/error，便于线上问题排查
- 添加 preloadRule 分包预加载（首页预加载健康/医生/文章分包）

P2:
- logout 时清理 ai_chat_history + BLE DataBuffer 缓存
- restore() 移除冗余的双重 Storage 读取（secureGet 已包含 getStorageSync）
- 首页文章图片添加 lazyLoad

apps/miniprogram/src/pages/pkg-profile/settings/index.tsx

@@ -1,6 +1,7 @@
 import React from 'react';
 import { View, Text } from '@tarojs/components';
 import Taro from '@tarojs/taro';
+import { safeNavigateTo } from '@/utils/navigate';
 import { useAuthStore } from '../../../stores/auth';
 import { invalidateHeadersCache, clearRequestCache } from '@/services/request';
 import { useElderClass } from '../../../hooks/useElderClass';
@@ -51,7 +52,7 @@ export default function Settings() {
   };
 
   const handlePrivacy = () => {
-    Taro.navigateTo({ url: '/pages/legal/privacy-policy' });
+    safeNavigateTo('/pages/legal/privacy-policy');
   };
 
   const handleLogout = () => {