[Feature]: 建议优化多步骤回复的消息聚合，避免连续发送多条碎片化消息 Feature Request — Aggregate Multi-Step Agent Responses to Avoid Message Spam

### 问题描述 / Problem Description

当前在对话中，当我向 Agent 提出一个任务后，Agent 在执行过程中会逐条发送大量消息卡片。比如一个操作涉及 10 个步骤，Agent 就依次弹出 10 条消息，导致聊天界面刷屏，体验非常差。

Currently, when I ask an Agent to perform a task, it sends multiple fragmented message cards one after another during execution. For example, a 10-step task results in 10 separate messages flooding the chat, which is a very poor user experience.

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### 具体痛点 / Pain Points

- 一条对话中连续收到 5-10 条 Agent 消息，内容碎片化
5–10 agent messages arriving in rapid succession for a single request, totally fragmented
- 消息通知频繁弹出，干扰正常沟通
Notification spam disrupts normal communication flow
- 无法快速获取任务的整体结果，需要上下翻动才能看完
Hard to grasp the overall result — need to scroll up and down to read everything
- 如果有多个卡片消息，视觉效果混乱，不像一个智能助手
Visually cluttered, doesn't feel like a smart assistant

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### 期望效果 / Desired Behavior

Agent 执行多步骤任务时，能够将过程消息智能聚合为一个整体回复。例如：
- 过程中不需要逐条汇报"正在进行第 N 步…"
- 全部完成后合并为一条结构清晰的结果消息
- 或者通过流消息 渐进式显示，或者通过编辑功能不断修改新增
- 或者至少显著减少消息条数，不要一题十答

When the Agent performs a multi-step task, it should intelligently aggregate the process messages into one coherent reply. For example:
- No need to report "Executing step N…" for each intermediate step
- Consolidate everything into a single well-structured final message
- Either through progressive display of streaming messages, or through continuous modification and addition through editing functions
- Or at minimum, significantly reduce message cards — don't send 10 replies for one question

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### 截图 / Screenshots

The issue does not name files, tests, or an entry point. Start by locating where multi-step agent execution emits chat messages and reproduce the reported 10-step case; done should mean one coherent final reply or a clearly reduced number of messages without losing the task result.

Scritto dal modello di indicizzazione a partire dal testo della issue.