feat(longtext): implement long text splitting strategy with Markdown …

[fdc310]

…awareness

概述 / Overview

请在此部分填写你实现/解决/优化的内容:
Summary of what you implemented/solved/optimized:

新增回复消息切割为多条消息回复逻辑

更改前后对比截图 / Screenshots

请在此部分粘贴更改前后对比截图（可以是界面截图、控制台输出、对话截图等）:
Please paste the screenshots of changes before and after here (can be interface screenshots, console output, conversation screenshots, etc.):

修改前 / Before:

修改后 / After:

检查清单 / Checklist

PR 作者完成 / For PR author

请在方括号间写x以打勾 / Please tick the box with x

• 阅读仓库贡献指引了吗？ / Have you read the contribution guide?
• 与项目所有者沟通过了吗？ / Have you communicated with the project maintainer?
• 我确定已自行测试所作的更改，确保功能符合预期。 / I have tested the changes and ensured they work as expected.

项目维护者完成 / For project maintainer

• 相关 issues 链接了吗？ / Have you linked the related issues?
• 配置项写好了吗？迁移写好了吗？生效了吗？ / Have you written the configuration items? Have you written the migration? Has it taken effect?
• 依赖加到 pyproject.toml 和 core/bootutils/deps.py 了吗 / Have you added the dependencies to pyproject.toml and core/bootutils/deps.py?
• 文档编写了吗？ / Have you written the documentation?

[RockChinQ]

这里query.resp_message_chain是不清空的？如果一个query里回复了好几条消息，会导致它重复发好几遍吧？比如在用户一个消息发过来时，local-agent执行了好几轮，那么每一轮都会产生一个回复，每个回复又会被split成好几份；原来的逻辑是只发最后一个resp_message_chain，一个message_chain不会被分割，就没有问题，但现在加了分割，可能就会有问题吧？

[fdc310]

query里为什么会回复好几条消息呢，有一点没有理解到，是相当于在群里，同时好几个人进行询问吗

[RockChinQ]

工具调用啊，agent循环，比如我让它去查询一个数据表，他就会回复：

1. 调用工具前回复一条“我将要调用工具”
2. 调用工具的记录一条
3. 完成后根据工具返回值回复“我查到了xxxx”

这样一次用户消息就有好几条回复的

[RockChinQ]

recheck

[github-actions]

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1 out of 2 committers have signed the CLA.
✅ (RockChinQ)[https://github.com/RockChinQ]
❌ @fdc310
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