Add Turns on the footer of the cli

### Describe the feature or problem you'd like to solve

As User I need a turns counter in immediate view so I know when to /compact

### Proposed solution

It is not practical to count my own turns when in the throws of solving the next corporate challenge using AI and agents .
I am focused on completing the challenge - not AI usage

In one of the recommendations by Claude Sonnet 4.5 - /Compact at turn 25-30 (not turn xx) → saves xxxM+ tokens per long session

Having the Turns easily in view will enable my cognitive memory to remember to /compact more frequently

### Example prompts or workflows

_No response_

### Additional context

_No response_

首先定位 CLI 页脚的渲染逻辑，以及 /compact 工作流使用的会话状态；该 issue 没有指定文件或测试。为页脚添加回合计数，并验证它在会话期间仍然可见且反映用户的回合数。

由索引模型根据 Issue 内容生成。