Whenever I try to start a new session on a large monorepo, it tries to create...

Whenever I try to start a new session on a large monorepo, it tries to create a worktree which fails. I can't find a way to turn that off.

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| Field | Value |
| --- | --- |
| App version | 1.1.2 |
| OS | macOS 26.5.2 |
| Theme | GitHub |
| Path | / |
| Tenure | Week 4 |

Issue 中没有指定文件、测试或入口点。使用报告中的 app version，在大型 monorepo 上复现 session-start 流程，并检查 worktree 创建是如何触发的。完成标准是用户可以在不创建 worktree 的情况下启动 session，并且该行为可以明确控制。

由索引模型根据 Issue 内容生成。