[Feature]: 基于qwenpaw 2.x的A2A何时支持

## Summary

qwenpaw已经完成了2.x的升级，架构文档中描述MCP/A2A/ACP会通过统一的Driver机制实现。但是当前代码中只支持了MCP，请问，A2A协议后续会官方支持吗？有没有计划时间何时完成？

## Component(s) Affected

- [x] 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

当前无官方的A2A协议支持，无法接入多Agent（尤其是外部Agent）协同。

## Proposed Solution

官方基于Driver机制实现A2A

## Alternatives Considered

官方or社区提供A2A插件。

## Additional Context

None

## Willing to Contribute

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