[Feature]:It is recommended to support direct rendering of line charts, pie charts and other charts within the session.

## Summary

问题：
- 生成图表后只能保存本地文件，**无法在聊天界面直接显示**
- 数据分析场景需要频繁手动打开图片，效率低

建议：
- 支持在会话界面**直接渲染折线图、饼图、柱状图**
- 支持 Markdown 图表语法或图片内嵌显示

场景价值：
- 提升数据分析、报表可视化效率
- 对标豆包/ChatGPT 等产品的图表能力
-这种需求对于个人及 B 端用户非常需要
## Component(s) Affected

- [ ] Core / Backend (app, agents, config, providers, utils, local_models)
- [ ] Console (frontend web UI)
- [ ] Channels (DingTalk, Feishu, QQ, Discord, iMessage, etc.)
- [ ] Skills
- [ ] CLI
- [ ] Documentation (website)
- [ ] Tests
- [ ] CI/CD
- [ ] Scripts / Deploy

## Problem / Motivation

[What problem does this solve? Who benefits?]

## Proposed Solution

[Describe the feature or change you have in mind. Be as specific as possible.]

## Alternatives Considered

[Any other approaches or workarounds you thought about.]

## Additional Context

[Screenshots, examples, links to docs or similar features elsewhere.]

## Willing to Contribute

- [ ] I am willing to open a PR for this feature (after discussion).