会话的保存、与工作区的关联，以及导出。
会话把一次完整的工作过程保留下来：对话、执行过程、产物和用量统计都归属于同一个会话。
会话保存在本机。它记录用户与智能体的会话、智能体执行的过程（读取和写入的文件、运行的命令）以及用量统计，方便随时回看。
每个会话可以关联各自的工作区：
这样，一个 Bi 进程可以同时推进多个互不干扰的项目。
可以置顶、重命名或删除会话。删除会话时，其中的会话记录会一并移除。
可以把会话导出为 Markdown 文件，保存在工作区内。导出内容为纯文本，包含提问、回复、思考过程、执行过程与结果，以及权限确认记录，方便归档，也方便交给其他 AI 工具继续处理。
How sessions are stored, bound to workspaces, and exported.
A session keeps one complete unit of work together: the conversation, the execution trail, artifacts and usage statistics.
Sessions are stored locally. A session records your conversation with the agent, what the agent did (files read and written, commands run) and usage statistics, so you can review it later.
Each session can bind its own workspace:
That lets one Bi process move several independent projects forward at once.
Pin, rename or delete sessions. Deleting a session also removes its conversation records.
Export a session as a Markdown file inside the workspace. The export is plain text containing your prompts, the agent’s replies, its reasoning, the execution trail and results, plus approval records — useful for archiving or handing the work to another AI tool.
