Toggle off for auto compaction!!!!

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

let me manage my own context window

### Proposed solution

Auto-compaction: No config toggle exists currently. It's hardcoded to trigger at 95% context. You can use /compact manually but can't disable
auto-compact. This might be worth a /feedback feature request.

### Example prompts or workflows

_No response_

### Additional context

_No response_

该 issue 提到了 /compact 命令以及在 95% 上下文阈值时的自动压缩，但没有指出任何实现文件或测试。首先定位自动压缩逻辑和现有的配置处理；完成的工作应包括一个有文档说明的开关，用于阻止自动压缩，同时保留手动 /compact 行为。

由索引模型根据 Issue 内容生成。