fix: 将birthday字段重命名为birth_date以保持一致性

 <!--
  * @Date: 2025-08-27 17:43:45
  * @LastEditors: hookehuyr hookehuyr@gmail.com
- * @LastEditTime: 2025-09-26 17:27:40
+ * @LastEditTime: 2025-09-27 16:09:23
  * @FilePath: /lls_program/src/pages/Welcome/index.vue
  * @Description: 欢迎页
 -->
@@ -204,24 +204,24 @@ useDidShow(async () => {
     userInfo.value = data?.user?.nickname ? data.user : {
       avatar_url: null,
       nickname: null,
-      birthday: null,
+      birth_date: null,
       wheelchair: null,
       wheelchair_text: null,
       phone: null,
     };
-    
+
     // 计算用户年龄
     if (userInfo.value.birth_date) {
       const birthDate = new Date(userInfo.value.birth_date);
       const today = new Date();
       let age = today.getFullYear() - birthDate.getFullYear();
       const monthDiff = today.getMonth() - birthDate.getMonth();
-      
+
       // 如果还没到生日，年龄减1
       if (monthDiff < 0 || (monthDiff === 0 && today.getDate() < birthDate.getDate())) {
         age--;
       }
-      
+
       userAge.value = age;
       // 检查是否满60岁，可以创建家庭
       canCreateFamily.value = age >= 60;
@@ -229,7 +229,7 @@ useDidShow(async () => {
       userAge.value = null;
       canCreateFamily.value = false;
     }
-    
+
     // 检查用户是否完善了个人信息
     hasProfile.value = userInfo.value.nickname && userInfo.value.birth_date && userInfo.value.wheelchair_needed !== null;
   }