Feature Request: Allow deleting / hiding project workspaces from the sidebar

[zhubaodian1027]

Problem Description

Currently, the sidebar groups sessions by project (cwd). Users can easily add a new project workspace via the directory picker when creating a new session, but there is no way to remove or delete a project from the sidebar once it has been added.

To remove a project, users currently have to either:

1. Manually delete every single session inside the project one by one through the UI.
2. Go to ~/.pi/agent/sessions/ and manually rm -rf the encoded project directory.

This makes workspace management cumbersome, especially when dealing with temporary projects, test directories, or outdated projects.

Proposed Solutions

Any of the following (or a combination) would greatly improve the UX:

1. Delete Project (Batch Delete Sessions)

   • Add a context menu or a "Delete" button (trash icon) on project workspace hover.
   • Show a confirmation dialog: "This will delete all N sessions under this project. Project files on disk will not be affected."
   • Behind the scenes, delete all session .jsonl files (or the project session folder) and invalidate the session list cache.

2. Hide / Archive Project (Soft Removal)

   • Allow hiding a project from the sidebar without deleting session history on disk, perhaps persisted in local storage or a config file.

3. Empty Project Cleanup

   • Automatically clean up / hide projects that have no active sessions.

Environment

• @agegr/pi-web: 0.8.11+
• OS: macOS