Preserve chats cross multiple machines under one account

### Feature summary

It would be nice to have my chats preserved as much as possible when logging into different machines using one account. They could be

### What problem are you trying to solve?

I have a dev laptop and a dev box. Sometimes I started to work from my dev laptop and later on figured out that I need to run some tests on my dev box. I would love to continue the conversation when I log in to different machines.

My dev laptop is a mac with arm. My dev box is a windows with x64.

### Proposed solution

Save the chat history under my account somehow.

### Workflow impact

_No response_

### Installation context

_No response_

### Additional context

_No response_

issue 中没有列出文件、测试或实现入口点。首先梳理 app 当前如何存储聊天记录以及处理账户数据，然后定义跨机器持久化的范围和验收标准，以便在所述的 macOS ARM 和 Windows x64 环境之间继续聊天。

由索引模型根据 Issue 内容生成。