feat(share): 更新分享标题显示用户昵称

- 修改分享功能使用用户昵称替代用户ID作为标题前缀
- 添加微信昵称存储逻辑到本地缓存
- 实现用户昵称、真实姓名或用户名的优先级取值
- 添加注释说明微信显示名称的存储用途

src/pages/index/index.tsx

@@ -20,9 +20,12 @@ function Home() {
   useShareAppMessage(() => {
     // 获取当前用户ID，用于生成邀请链接
     const userId = Taro.getStorageSync('UserId');
+    const user = Taro.getStorageSync('User') || {};
+    const nickname =
+      (user && (user.nickname || user.realName || user.username)) || '';
 
     return {
-      title: userId + '超值推荐',
+      title: (nickname || '') + '超值推荐',
       path: userId ? `/pages/index/index?inviter=${userId}&source=share&t=${Date.now()}` : `/pages/index/index`,
       success: function () {
         console.log('首页分享成功');
@@ -164,6 +167,7 @@ function Home() {
     Taro.getUserInfo({
       success: (res) => {
         const avatar = res.userInfo.avatarUrl;
+        // Keep WeChat display name in storage so share title can use it.
         console.log(avatar, 'avatarUrl')
       }
     });