fix: duplication of text memories and preference memories

[endxxxx]

Pre-submission checklist | 提交前检查

• I have searched existing issues and this hasn't been mentioned before | 我已搜索现有问题，确认此问题尚未被提及
• I have read the project documentation and confirmed this issue doesn't already exist | 我已阅读项目文档并确认此问题尚未存在
• This issue is specific to MemOS and not a general software issue | 该问题是针对 MemOS 的，而不是一般软件问题

Bug Description | 问题描述

duplication of text memories and preference memories

How to Reproduce | 如何重现

example:
The user plans to travel with their whole family during the summer vacation, including children and elderly people.

The user plans to travel with their whole family during the summer vacation, including children and elderly people; it is usually a family trip.

Environment | 环境信息

Python version: 3.11

Additional Context | 其他信息

No response

Willingness to Implement | 实现意愿

• I'm willing to implement this myself | 我愿意自己解决
• I would like someone else to implement this | 我希望其他人来解决