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_

該 issue 提到了 /compact 命令以及在 95% 上下文閾值時的自動壓縮，但沒有指出任何實作檔案或測試。首先定位自動壓縮邏輯和現有的設定處理；完成的工作應包括一個有文件說明的切換開關，用於阻止自動壓縮，同時保留手動 /compact 行為。

由索引模型根據 Issue 內容生成。