Close workspaces from the GUI

Branch: codex/close-workspace Created: 2026-09-29 Status: Ready

User story

A user can close a workspace from its sidebar row, or close the active workspace from the main menu. A confirmation names the workspace and warns that its running terminals and agents will stop. Cancel leaves it intact; confirm removes it from the GUI after the server accepts the request.

Acceptance scenarios

1. Given two workspaces, closing either from its row targets that row's id, even if another workspace is selected.
2. Given an active workspace, the menu's Close Workspace action targets it.
3. Cancel or Escape sends no workspace.close request.
4. Confirm sends exactly one workspace.close request. On success the sidebar and active content refresh; on failure the workspace stays visible and a toast reports the error.
5. Repeating a close action while its confirmation is open does not open a second confirmation.

Scope and assumptions

• Reuse the existing workspace.close IPC method and its process handling.
• Closing a workspace does not delete its project directory.
• No new server method, persistence format, or model field is needed.